Solid Skies
by Veldeia
Summary: After surviving one big cave, the 10th Doctor, Martha and a caving team from the Sixties find themselves in even more trouble - from Plague to politics - on a planet full of caves. Sequel to Hollow World.
1. City of Lights, Upper North Entrance

**Author's Note: **This is a direct sequel to "Hollow World", and completely spoils that fic. Nevertheless, this is an entirely different story, both plot-wise and style-wise. Also, you may need to wait quite a few chapters before there's any whump - but rest assured, there shall be some ;)

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**1. City of Lights, Upper North Entrance**

"So, how do we get down there?" Martha asked, gazing at the magnificent view before them: the mind-bogglingly huge cave chamber, and on its floor, hundreds of feet below the platform they stood on, the city with its countless lights, in more colours than she could name. "I really hope it doesn't include free fall, crawling, climbing, squeezing through tight places, or wading in ice-cold water." Her right wrist still ached in memory of the adventures they'd had in a cave on Earth.

"We could just take the lift," Jess told her, nodding backwards at a door in the smooth rock wall right next to where the TARDIS stood. Martha had completely missed it earlier. "But I recommend the scenic route," Jess gestured to their left, where the parapet in front of them went on for several more feet, and then dipped down, apparently forming one edge of a stairway.

Short, sinewy and pale, with close-cropped white hair and light yellow eyes, Jess was a Khiandrian - a native of the planet they currently stood on, a world where all the inhabitants lived in a vast network of caves beneath the barren surface. She had been in self-imposed exile on Earth for twenty years, from the late 1940's to the 60's, but now, after they'd survived a nerve-racking trip through Lechuguilla Cave in New Mexico, the Doctor and Martha had brought her back home with her human boyfriend and the two other members of their caving team.

"I vote for the scenic route," Joseph, the stocky cave photographer spoke up.

"Oh yeah, me too," agreed Grant, the grey-haired geologist, the stern leader of the caving party.

"What are we waiting for, then?" the Doctor exclaimed, already heading for the stairs in brisk steps.

Brian, Jess's boyfriend, a rather handsome school teacher in his thirties, stopped him with a question. "Doctor, wait - what about the petromites?"

The Doctor came to a quick halt and spun around. "It always comes down to that, doesn't it? What about the petromites. But they're home now - we could just open the doors and let them loose. This is their natural environment, after all." He raised his eyebrows at Jess. "What do you think?"

The petromites were another species native to the planet, a species of termite-like insects, which ate rock, and built beautiful crystal castles for their queens. Some had stowed away with Jess when she had run away from the planet as a teenager, and if Martha and the Doctor hadn't run into them on Earth and brought them here, they might have caused major mayhem there. Martha had assumed the problem was entirely sorted now that they'd brought the petromites back home.

"Um, no, I don't think that would be a good idea," Jess replied. "That's the population of an entire nest we have there. We don't know how many petromites are already in this area, whether the ones we brought could join an existing nest or if they'd need to start building from scratch, and anyway, they'll need a caretaker, and there are rules and regulations to follow, so..."

"So, they'll have to wait in the TARDIS until we've contacted the local authorities," the Doctor said, looking slightly taken aback. "What if they get hungry in the meantime?"

"I already told you they're too puzzled by your ship to touch it, didn't I? Besides, if they find themselves stuck in a hostile environment - like without food - they'll go into hibernation. They can survive for long periods almost anywhere. That's one of the reasons why they're so good at spreading to other planets."

"All right, then. A little hibernation never did anyone any harm. More like the opposite. I'm living and concussion-free proof of that!" the Doctor declared, with a wide grin. "Now that's settled, let's go see the sights!"

He lead the way to the stairs and down. Martha followed him, and the cavers came behind her. The stone steps were so steep that she had to keep looking at her feet, but she did catch a few more glimpses of the city. She felt like she could stare at it for hours, and everyone else seemed to be feeling the same way. The Doctor was staring at the view so intently that Martha was amazed he didn't trip on his feet and fall on his nose. Joseph and Grant kept pointing out details to each other, both about the city and the vast cavern, which looked natural, although Martha figured the Khiandrians must've made it bigger, somehow.

"What about those straws and stalactites up there, in the ceiling, Jess?" Grant asked. "They've got to be pretty big. What if one of them grows so heavy that it breaks and falls?"

"That won't happen," Jess assured him. "There are force fields to prevent that sort of thing. If one should fall, it would be pulverised and just rain on the city as fine dust."

"Should I know what a 'force field' is?" Joseph said.

"Oh, your people won't invent those in many, many years," the Doctor told him.

The descent was a long one. Martha wondered how many hundred stairs there were - she hadn't been keeping count. The stairway was carved from the rock face itself. Every now and then, there was a small landing, and the stairs changed direction, forming a wide zigzag pattern in the cliff side. The last landing, however, was bigger than the rest, and the last flight of stairs was wide and massive, at a right angle to the rock face. It rather reminded Martha of the stairs in front of a museum or a temple, making the final approach particularly impressive.

Where level ground began, so did the city. There were some edifices in the cliff side itself, including, by the looks of them, a gift shop and several cafés and restaurants. Martha couldn't even imagine what sort of food they would eat down here. Not far from the wall stood the first buildings. They came in all sizes and shapes, from tall pillars, like artificial stalagmites, to strange crystal clusters, like the khirindals in petromite nests. There were some perfectly unremarkable, rectangular houses as well, which could've been from anywhere on Earth.

"It's so... different!" Brian breathed. He was holding Jess's hand.

"This is probably the most familiar-looking place you'll see on the planet," Jess told him. "There aren't many cities that are built like this, all out in the open."

"Oh," he said, surprised. "There's so much I don't know about your home! I want to learn everything. Where do we begin?"

"Actually, we should tend to the official matters first - and before anything else, I need to contact my family. My uncle used to live here, at a walking distance from where we are. Let's see if I can still remember the place, and if he's still there."

Jess guided them to a street between low buildings, which Martha took for a residential area, with both detached and row houses. Some of the houses had gardens, with intricate displays of stones and crystals and strange cave formations, as well as alien plants, mosses and lichens. From a close distance, she noticed the buildings had less windows than those on Earth usually had, and there was no glass in them. Maybe they used force fields - or maybe there really was nothing. They were deep underground, after all. The weather must be very stable.

There were people about, of course, adults working in the gardens or walking on the streets, minding their own business, and children playing. They all resembled Jess, almost all of them shorter than Martha and very pale. Their hair colour varied from white and grey to different light browns, their eyes from blues and greens to yellow, purple and red, although it was hard to tell the exact shades, when the lights were multicoloured and a little too dim for human eyes.

Two things about the Khiandrian crowd drew Martha's attention. First of all, many of the adults, and some of the children, seemed to be wearing a badge - a small, round button, around two inches in diameter. Most of them were black, a good number were grey, and she spotted a few white ones, too. No text, no picture, just plain buttons of a single colour. Her first, alarming thought was that it was some sort of a segregation thing, but no matter how she looked, she couldn't see anything in common with the people wearing a certain colour.

The second thing she realised was, the Khiandrians were staring at the humans and the Doctor, every bit as curious and wide-eyed as they were. Some children even stopped and pointed fingers at them. She spotted frowns and scowls, too, and some adults turned their heads and hurried away, as if making an effort to ignore them.

"They don't get a lot of... foreigners here, do they?" Joseph asked.

"No, but they do, actually," Jess answered. "This is weird. The City of Lights is one of the biggest tourist attractions on the planet, all off-worlders come here."

The Doctor, who had been waving at a group of children eyeing him suspiciously and whispering to each other, froze on the spot. He let his hand fall, his goofy grin giving way to a frown, and turned to look at Jess. "Or, they used to come here. What year was it when you left?"

"4358, in our years. Don't know about Earth years."

"And you were gone for twenty Earth years. That would mean it's around the early 4380's now... Hmm."

"Don't tell me you actually know my planet's entire history!" Jess cried out.

"I won't, because I don't. Your people haven't exactly been talkative about it. Especially not about the crisis of the Four-Three-Eighties. There was one, I know that much. What it was about, I have no idea. Maybe it was about us! I hope not, though - but if it was, well, nothing we can do about that," the Doctor said, with a shrug.

Whichever the case, the group was much more subdued as they walked on, trying not to pay attention to the gaping locals. They crossed what looked like a major street, with many people, lots of brightly lit edifices, and two sets of tracks for little trains or trams, which seemed to be hovering several inches above the ground. No cars anywhere, just public transportation, by the looks of it.

After another ten minutes of walking through smaller streets and alleys, they stopped in front of a small two-storey house. It looked exactly like a huge boulder with a door and a few randomly placed holes for windows.

"Dear uncle T'ig," Jess said fondly, the "t" at the beginning sounding more like a sneeze than anything else. "We are lucky, he's still here."

Martha wondered how Jess could be so sure about that. She couldn't see a name plate, or anything like that. Come to think of it, she hadn't even seen any signposts along the way. Maybe the Khiandrians could tell by smell or sound, or some little detail that foreigners wouldn't know to look for.

Jess stepped closer to the door, gave it a single knock, and called out, "T'ig? It's me."

The door slid open, revealing a very confused-looking Khiandrian. He was the same height as Jess, but considerably rounder, and clearly many decades older, with a wrinkly face and a crouched posture. His eyes were yellow like hers, and his hair was shoulder-length and grey. Martha noted he didn't seem to be wearing one of the buttons.

"Bless me! My dear little Jez!" T'ig beamed at Jess, and pulled her into a hug. It was only after he'd let go of her that he seemed to take in the rest of them. He froze for a beat - and panicked. "Oh, dear!" he cried out, pulled Jess in by the hand, and gestured urgently at everyone else to follow, muttering, "Come on, come on, quickly, now, don't just stand there! Oh, hurry up, before someone sees you!"


	2. Amber Pass 8R

The old Khiandrian closed door behind them, and stood there, staring at them. "Jess, dear..." he muttered. "You... I didn't think I'd ever see you again, little Jez - the things they said about you... But your friends here, they're - you're - they - you..." His voice trailed away, and he blinked, and opened and closed his mouth, like a blind cave fish on sunny, dry ground.

"I think we'd better sit down and talk things through," Jess said. "Come on." She took T'ig's hand and lead him deeper into the house.

The Doctor and the others followed the two Khiandrians. T'ig's home seemed sparse in furniture, but rich in decorations. The walls were covered with art - modern-looking abstract 3D-pics, older paintings and drawings of buildings and people, and both 2D and 3D photos of caves, cave formations and prehistoric art. All the lights inside the house were the soft green typical to most places on Khiandria. There were small sculptures and frames with more pictures on every tabletop and other spare surface. The room down the hallway was a sitting room, with chairs that looked like rocks, with moss for cushions. On closer inspection, they were enitrely artificial, of course.

T'ig sat down, still gaping at his unexpected visitors. Jess took a seat next to her uncle, placing a hand on his back. "It's all right, T'ig. I'm really here. I'm back."

"They said you'd run away - flown away with your mother's ship, no less - I told them you wouldn't do such a thing, you're independent and adventurous, sure, but a criminal - never!"

"Actually, it's true," Jess said sadly, looking down. "Every word of it. But now that I'm back, I'm going to take full responsibility for what I did."

"Jez, you must be joking! How can it be true? And these friends of yours! They're aliens!" T'ig blurted out.

"Yes, they are. T'ig, meet Brian, my mate, and my friends, Joseph, Grant, Martha and the Doctor," Jess said, pointing them out to her uncle.

"Your mate, you say! But, but - they're not even allowed outside Maze City, haven't been for two seasons - if the guards saw you wandering around with them... Unless you have official clearance?"

"Of course we do," the Doctor put in. He had his psychic paper, after all. Universal clearance.

Jess gave him a puzzled look, and crossed her arms. "If we hadn't, though, what would happen? And since when do tourists need a permission to visit the City of Lights?"

"Ever since they declared a planet-wide state of emergency, of course! Honestly, I have no idea what would happen. I don't think there's ever been an incident like that before, aliens just popping up here without clearance. Better hope they didn't see you, and that no one reported you. How did you even get here? I'd have thought you'd have no choice but to stay in Chute Town!"

"We didn't come through there," Jess said, starting to look uncomfortable. "We used a ship that's a little different. No need for a spaceport. But what do you mean, no choice? What's going on here? I've been gone for decades, T'ig. I don't understand. What's happened?"

"Decades? Has it truly been so long? You barely look any older. What's going on, what's happened, oh, where to begin? Politics, that's what it all comes down to, I guess. Almost everything. It's been going on for years, both Darks and Brights gaining in popularity, and then, half a year ago, the Plague came, and the situation just exploded. We've got all the emergency laws, the Darks are more popular than ever, and the ones who are still Brights are all the more fanatical, and -"

"Wait, wait, what?" Jess waved a hand to stop T'ig's flow of speech. "Plague? Are we safe? Is everyone all right?"

"We're not in any danger, the outbreak happened far from here. Your parents are fine as well, and your sister and her family, but your grandmother... I'm afraid she was stuck right in the middle of it. I'm sorry."

Jess stared at him, biting her lip, her face blank, as if she had trouble understanding what he'd said.

T'ig looked at her sadly. "It's been a very difficult year for all of us, and it's only getting worse. As if the Plague wasn't bad enough on its own, it's been turned to politics, too. The Darks think the current laws aren't strict enough, the Brights think they're way too strict, and they're both very active in promoting their views. With the elections coming up, it's chaos - I doubt the planet has seen this much violence since the early 4000's. And they're all talking about aliens, even though the truth is, we can cause more trouble on our own than aliens ever did."

"Does this all have something to do with those buttons everyone's wearing?" Martha put in. "Black, grey and white?"

"Dark, Dusk and Bright, yes, yes, well spotted," T'ig said, nodding. "People showing their allegiance. I'm really not into politics. I guess you could call me a Dusk. I really don't know much about it all."

"Well, we know even less," Martha said. "Please, sir, if you could try and explain?"

"I can try, but don't blame me if I get something wrong. So. There are the two extremes, Darks and Brights, and us Dusks in the middle. The current Chairperson is a Dusk, but I'm afraid that's going to change. The Darks have gained a lot of ground after the Plague. Officially, they're called the Preservationist Party, because they want to preserve all Khiandrian life, which means as little contact with aliens as possible. And the Brights, that's the nickname for the Diplomats. They'd welcome all aliens with open arms, no questions asked."

"That's not so complicated," the Doctor noted. "You have xenophobes, xenophiles, and neutrals."

"Oh, but then each party has dozens of different factions, from peaceful protesters to aggressive activists, there's environmentalists, technologists, anarchists, monarchists, who-knows-what-ists - I doubt anyone can keep count of them all! I can't, that's for sure."

"That's politics for you, all right. It's the same where we're from," Brian commented.

"It's the same everywhere in the universe," the Doctor said. "Even when you have a really simple system, like on Vyrondia, where the same emperor has been ruling for a thousand years - nice chap, rather reminds me of an opossum - there's still the endless bickering and plotting and scheming." He pulled a face. He'd rather avoid getting messed up in local politics, if he could.

He was about to ask T'ig about the Plague, when all of a sudden, the old Khiandrian leaped up from his chair. "Oh, no! They're here!"

The Doctor hadn't heard or noticed anything, but Jess stood up, too, gazing towards where the door was, tilting her head. "The guards," she said tonelessly.

A few seconds later, there was a loud thud at the door, and a strict alto called out, "Open! In the name of the State!"

"I have an emergency exit, through the roof," T'ig said in a voice so low the Doctor could barely hear it. "If you hurry up..."

Jess shook her head. "No. They've already heard we're here. Besides, I decided not to flee from what I've got coming. You don't need to stay, though," she told the others.

"I'm staying with you," Brian announced.

"If there's any trouble, we may be able to help," the Doctor said.

"Yeah," Martha agreed. "We're not going to abandon you."

Joseph and Grant exchanged a glance. "And we're on an alien world where we understand absolutely nothing about anything. What would we do on our own?" Grant said.

The knock and shout were repeated, and in silent agreement, the entire party walked over to the small hallway. T'ig opened the door. Behind it stood two Khiandrians in spacesuit-like protective clothing, a man and a woman, their faces visible beneath the clear face plates. A few steps behind them was another woman, tall and burly by Khiandrian standards, wearing a dark uniform.

"By Khar's Fall, it really is true! So many aliens!" the tall Khiandrian exclaimed, the startled expression looking out of place on her stony face. "I'm Getl, Head of Guard, Northwest District. Here to investigate your illegal invasion of our fair city. Go ahead, check them," she told the pair in protective suits.

"No, wait! We're not illegal aliens, we've already been checked and cleared," the Doctor said quickly, pushing the psychic paper at them.

"Oh, you have, have you?" Getl said sarcastically.

"Ambassadors from Gallifrey and Earth, under the special permission of Her Honour, the Chairperson," one of the hazard team read aloud.

"I don't know what you're playing at, but I'm not falling for it," Getl declared. "'We already checked, and there are no registered aliens who've been given permission to leave the capital. I don't know how you got here, but under the article a-N of the Emergency Law, you're going to go through a full bioscan, either with your co-operation, or without it."

"It's okay, I guess," Jess said in an undertone. "Just a scan."

"It's okay," T'ig agreed. "Let them enter."

The hazard team took over the living room, and sent everyone upstairs, where T'ig had his kitchen and bedroom, with orders to show up for the scan one at a time. The Doctor volunteered to go first, to make sure it was all right, which it was, mostly.

The man in hazard gear told the Doctor to stand still, and crouched to the ground, to start running a handheld scanner of some sort along his body, from the toes up. The tip of the device almost touched his clothes, and the man was moving it very slowly, peering closely at the small screen.

"What're you looking for?" the Doctor asked, curious. "That Plague of yours?"

"That, or any other potentially harmful alien pathogens."

"You won't find any, I can promise that. I've got the best immune system you're ever going to see."

"That's good for you," he said, like he wasn't really listening.

While the man went on with his scan, the woman took up asking the Doctor a set of basic questions. Of course, he had a hard time coming up with any answers that she'd accept.

"Name?"

"The Doctor."

"That's not a name."

"You can't believe how many times I've had people tell me that. All right. Doctor John Smith."

"John Smith. Homeworld?"

"Nowhere in particular."

"What's that supposed to mean? That card of yours said Earth and Gallifrey. Neither of those, then?"

"You won't find either in your database, so it doesn't really matter, does it?"

"Okay. Homeworld: unknown, then. Species?"

"Not in your database, either."

She sighed. "So, you're an alien of an unknown species, from an unknown planet. Lovely. Please list the planets you've visited during the previous year."

"A year in my personal timeline, or the planets'?"

"Oh, just answer the question!"

"But it makes all the difference! During the last year or so, I've visited... Let's see - do you count moons? Asteroids? Satellites? Independent space stations? What about planets that aren't inhabited at this time but will be? Or were, but aren't, anymore? It might be easier to list where I haven't been, actually."

At this point, the man with the scanner had reached the Doctor's hair, and stepped back, apparently satisfied. "All clear," he declared.

"I think I'm done here, too. You're free to go," the woman said, looking quite happy to get rid of him. "Send one of the others after you. You can tell the two locals we'll need to scan them as well, since they've spent time with the bunch of you."

Martha went next, and came back five minutes later, flexing her wrist. "They fixed the sprain, just like that. Just as a courtesy," she told them, looking baffled.

"Pretty advanced medicine, by the looks of it. Seeing how advanced your people are, if the Plague has made your government this paranoid, it must be really nasty," the Doctor said, addressing T'ig. "What's it like?"

"I only know what they've said on the news. It was brought here by an alien. The Crystal Plague, that's what they call it, or the Diamond Death. It first started spreading among the petromites around Nest Town, but it soon hopped species to us."

"And my grandmother lived there," Jess said softly.

T'ig nodded, looking every bit as miserable as his niece. "Before they managed to contain the Plague, it killed millions of petromites and hundreds of people. Nest Town is a ghost town now, and under quarantine until further notice."

"And Nest Town is a suburb of Maze City - that's the capital," Jess told the Doctor and the humans.

"We're very lucky they stopped it before it spread any further, but the threat is still there," T'ig said.

"What kind of a disease is it, then?" Martha asked. "What are the symptoms?"

"It turns you to crystal, somehow. It's absolutely lethal, and there's no cure," T'ig replied, his voice slightly shaky. "No one who gets it survives."


	3. Northwest District

Once everyone had been scanned and deemed acceptably clean, Head of Guard Getl met them at the front door again. She obviously didn't want to come inside. It seemed she wasn't entirely convinced that she wasn't going to catch some horrible deadly alien disease from them.

"So, the bio team has given you their OK, but that doesn't mean you get to walk around freely," she said, every bit as unfriendly as before. Martha noted she was wearing a Dark button. No surprise there. "Five aliens and a fugitive who's best mates with them... Never have I witnessed anything like this. You're under house arrest until Central Command figures out what to do with you."

"And how long's that going to take?" the Doctor asked.

"Could be a tenth, could be a cycle. Can't say, since there's no precedent. Don't even think about trying any alien trickery while you wait, there'll be guards at the door round the clock." She made some sort of a salute, bringing her right hand to cover her eyes, and slammed the door shut.

"Blast it!" Jess growled, and punched the door with both fists. "The old travel rules were overly strict, but this is just insane! I thought I was going to be in trouble, I didn't mean for everyone else to get caught in it, too, when you've done nothing wrong! I should never have brought you here."

"Come, now, dear," T'ig said, and reached to put a soothing hand on her shoulder, their previous roles reversed. "It's not your fault. You couldn't have known about the current situation."

Jess shook her head, still looking gloomy. "I think I'd better give my parents a call."

"I'm not entirely sure that's a good idea," T'ig said, in an odd tone.

"They should learn about our arrival from me, not from the news," Jess said firmly.

"Hm. You're probably right," T'ig agreed. "You can use the terminal upstairs. Everyone else, please, make yourselves at home."

The two Khiandrians headed up the stairs, while the others returned to the living room. Martha and the other humans took seats on the surprisingly comfortable chairs. The three cavers were looking like they had no idea what to think about all this. The Doctor didn't sit down, but started pacing the room like a caged animal, even though they'd only been captives for a few minutes.

Maybe ten minutes later, T'ig came downstairs, holding a tray with a plain white tea set and a platter full of small, round, almost white biscuits. Martha smirked. She'd been wondering what Khiandrian food was like, and she definitely hadn't been expecting tea and biscuits.

Jess followed T'ig into the room, and Martha's grin faded quickly when she saw the look on her face - it was even more miserable than before. Jess went straight to Brian, and sat next to him.

Brian put an arm around her shoulders. "Jess? What happened? Is everything all right?" he asked softly.

Jess let out a deep sigh, and shook her head. "My parents. They... They very nearly refused to talk to me at all. They're still mad at me, and when I mentioned you... I only explained to them that I came here with alien friends, and they cut the connection."

"Ever since the loss of your mother's mother, they've been ardent Darks," T'ig said.

"How am I supposed to explain to them that I'm in love with an alien and want to spend the rest of my life with him?" Jess groaned, snuggling even closer to Brian.

"Maybe they just need time," Brian said hopefully, stroking her hair.

"I'm sure things will work out, somehow. Here you go, dear," said T'ig, and offered Jess a cup of tea.

They ate and drank in silence for a while. The tea was very much like green tea at home, with maybe a hint of cinnamon, and the biscuits were very sweet and very crunchy, rather like meringue.

While everyone else sipped at their tea, the Doctor kept juggling a biscuit between his hands. Finally, he broke the silence. "Tell me, T'ig - what do you suppose the people in charge are going to do with us?"

"I don't know, really. There haven't been any alien offenders since the Emergency Law came into force. I suppose there's going to be a full trial, unless your governments interfere. As for possible sanctions... They could just banish you, but that might be too much like letting you go. More likely they'll send you to the Dungeon Moon. Worst case scenario would be decades. If you manage to convince the jury that it was a misunderstanding, it might just be months."

Martha saw the cavers turn to stare at the old Khiandrian, horrified. Months or years, even decades of imprisonment on an alien world? It definitely wasn't a cheerful thought. Still, she wasn't feeling overly worried. After all, they weren't in prison yet.

The Doctor didn't seem upset, either, just thoughtful. "All right. So. You said something about a second exit earlier? Through the roof?"

"Yes. You're not planning on escaping, are you?" T'ig asked, lowering his voice, as if afraid the guards outside might overhear.

"Well, the thought had crossed my mind. Better make our exit now, when it's still easy. If one or two of us could get to the TARDIS," the Doctor said, glancing at Martha, raising his eyebrows, "They could come back and pick up the others before the guards can say 'bailed by a big blue box'."

Martha set down her teacup. "Let's go, then!"

"It might not be that easy, even if the guards haven't noticed that exit and aren't guarding it," T'ig noted hesitantly.

"Don't worry, I've done this sort of thing hundreds of times. I'm a true escape artist if there ever was one!" the Doctor declared.

"Well, then, I suppose you know what you're doing," T'ig said. "Follow me. The rest of you, keep talking. They'll grow suspicious if we all fall silent."

T'ig took Martha and the Doctor upstairs, and there to his bedroom. Just above the low bed, there was a trapdoor in the ceiling. "That goes through to the roof, and from there, it's an easy climb down, with clear holds in the back wall. You'll end up in the passage behind the house. Do you know your way from there?"

"Sure we do, that big cliff with stairs is a good landmark," the Doctor assured him. "Don't worry, we can take care of ourselves."

"And sorry about causing you all this trouble," Martha added.

"Never mind that! You brought back my favourite niece. I'm prepared to handle a little trouble because of that. Now, as soon as we open that hatch, we must be very quiet. I wish you safe ascents and easy descents, friends."

T'ig used the stone wall by the bed to climb up a few feet, and pushed the trapdoor open. The Doctor went through it first, with ease, since he could reach the sides of the opening while he stood on the bed. Martha needed a little help from him and T'ig, but after everything they'd done in the cave on Earth, this was nice and easy.

She clambered to the roof, and with a final wave at T'ig, closed the hatch as quietly as she could. The Doctor grabbed her sleeve to catch her attention, and pointed out first the front door, where the guards stood - she could just see the tops of their heads - and then the alley behind the house and the pitch leading down to it. The way down might have been easy for a Khiandrian, but to Martha, it looked anything but. Although she could see the crags and knobs that were the hand and footholds, it was no ladder, and even though it wasn't immensely high, it was still a two-storey drop.

Without wasting any time, the Doctor began climbing down. Martha waited until he was safely on the ground, then sought out a set of good holds, and followed him. She did her best to make as little noise as possible, although every whisper of cloth or skin against stone sounded horribly loud to her. She concentrated very hard on each hold, on each single move, only moving one limb when she was sure the three others were completely secure. The stone was so coarse under her hands that it felt like it might cut her fingers. She dared not look down. Finally, her feet found solid ground.

The Doctor was waiting for her, and gave her the thumbs up. Then, he turned away from her, probably looking for the cliff with the stairs. Thanks to that, when a guard emerged from the narrow space between the boulder-like house and the one next to it, the Doctor had his back turned to them.

"Hold it right there. You, tall alien, turn around slowly," the guard ordered. "You honestly thought we wouldn't hear the racket you made when you scrambled down?"

The Doctor did as he was told, but from the corner of her eye, Martha saw him grab the sonic screwdriver and thumb the button. All of a sudden, a piercing whine cut the air. It was nasty even to Martha's ears, and to a Khiandrian, it must've been downright painful. As the guard doubled over, hands over his ears, the Doctor and Martha were already running.

Martha wasn't sure if the Doctor had any idea where they were going. They just ran, as usual. They took the first turn right, and then, right after that, a sharp left. They rushed through small, narrow alleys, some of them covered, very tunnel-like. They even dashed across someone's garden, almost running into the old woman who was crouched amongst the flower beds.

She heard a zap, and something hit the ground by her feet. She looked over her shoulder to see a guard at the far end of the street, pointing a gun at them. How could the guards still be following, after all the crazy turns they'd been taking?

Another shot whizzed past them - and then, just as they were heading for another narrow passageway, the Doctor went down with an "Oof!", landing face first in the dirt.

Martha knelt by his side to see how bad it was. Not bad at all, apparently. He looked up at her, already getting up on his elbows.

"A basic stun gun," he told her, grimacing and slightly out of breath. "Will take more than that to stop me!"

She helped him to his feet, and then, they were running again. After a few more random, sudden turns, they found themselves on the big street they'd crossed on their way to T'ig's place. There was a team of guards standing there, blocking the way. The Doctor and Martha doubled back to the side alley they'd come from. Luckily, they'd managed to put some distance between the guards who had been behind them.

Martha looked around frantically for a hiding place of any sort. The Doctor shook his head. "There's no point. They'd smell us anyway." Only then she realised that must've been how the guards had been following them all along.

Three guards appeared at the far end of the alley, and four stepped into it from the big street, all aiming guns at them. They were surrounded.

"Will you come nicely, or do we need to stun you?" one of the guards asked.

The Doctor hung his head, his hands in his pockets. "We'll be nice. Promise," he said meekly.

Their return trip was a subdued affair, and the distance was much shorter than Martha would've expected. They must've been running around in circles when they'd tried to shake off their pursuers.

"Just so you know, no point in trying any more sonic tricks. Half the team will be wearing earplugs from now on," the guard announced, as he closed T'ig's door after them.

They returned to the living room, to face the worried and disappointed glances of the others.

"A true escape artist, eh?" Grant sneered.

"Even artists need to practice," the Doctor retorted. "Time for plan B. As soon as I've figured out what that is."


	4. South Entrance

Bummer. The Doctor had known Khiandrians had extremely keen senses, but he'd been hoping all the smells and sounds of the city would be enough to throw them off. He had definitely learned his lesson in that matter.

"I don't suppose your house has a secret third exit?" he asked T'ig hopefully.

T'ig didn't look the slightest bit amused. "No, it doesn't."

"Thought so. Well, no harm in asking. So, both exits are guarded, and -"

A demanding knock at the door stopped the Doctor's train of thought before it had even left the station. It was Getl, back with news. So much for plan B.

"The higher-ups don't seem to know what to do with you, either. We've been given orders to escort you to Maze City. T'ig, son of Sekh, your case will be handled locally, and you remain under house arrest. The rest of you, out. We're leaving."

A dozen guards surrounded them as they left T'ig's place behind. A dozen armed guards plus Getl, as opposed to the Doctor, Martha, and the four cavers, armed with one sonic screwdriver, which wouldn't be half as useful as before, since every other guard now wore earplugs. Nevertheless, as they marched through the streets, past a crowd of curious onlookers, the Doctor could've easily come up with a dozen ways to flee from the guards. The problem was, he knew he'd get caught again right away. It would be very hard to hide here, when he was so clearly alien, looks, smells, sounds, every single detail. He doubted he could get to the TARDIS unnoticed.

He considered making a dash for it anyway, but before he actually got to doing that, they were ushered into a small tram, with standing room only. It was a fully automatic one, by the looks of it - Getl just filled in their destination, and hit "go".

"So, where are we going?" the Doctor asked her, hoping against hope that they might end up in a situation where it would be easier to try and escape.

"South Entrance," Getl answered briefly. "Lift to the surface, then the train to Maze City."

The Doctor leaned back against the railing by the windows. Martha and the others kept glancing at him, clearly expecting him to come up with a plan. Unfortunately, he was short on ideas. He could easily wreck the tram with the sonic screwdriver, but once again, what good would that do?

Maybe he was going about this in the wrong way. Did they really need to run away right now? There were obviously major problems on the planet, and they might be able to help. Where better to start looking into those than the capital?

"Well, I always wanted to see Maze City," he said aloud, hoping the others would catch his drift. "I'm sure we can sort everything out over there."

The tram took them through the city, past church-like buildings with towers and spires reaching for the dark ceiling, past offices and schools and a sports stadium of some sort. Eventually, they reached their destination: the very edge of the cavern, right across from the cliff where the TARDIS still sat. There, climbing up the wall, was a row of lifts with transparent walls, like in some modern hotel or office building on Earth. They followed the slight curve of the wall for maybe a hundred feet, then disappeared into dark holes in the rock.

"The three of you," Getl gestured at the Doctor, Martha and Joseph, "Take that car. You, with them." She singled out four guards. Another four guards were given the orders to accompany Jess, Brian and Grant in the adjacent car. "Khif, you're in charge from now on," Getl added to a guard of the first team, who rather looked like a younger, shorter version of herself.

"You're not coming with us, then?" the Doctor asked conversationally.

"To Maze City? No time. I have my duties here. Enjoy your trip. It may be the last you'll see of our beautiful planet," Getl said ominously, made the Khiandrian salute, and returned to the tram with the remaining four guards.

The captives were ushered to the cars, which instantly began ascending slowly, clearly designed to give visitors another impressive view of the city. The guards took positions in the rounded corners of the small metaglass-walled space. Joseph stood at the front, gripping the handrail with white-knuckled hands, his expression tense, but curious nevertheless. This was probably his first time in a lift like this. Martha and the Doctor gazed at the landscape over his shoulders. It was still every bit as beautiful as before.

After a few minutes, their lift left the cavern, and then, there was nothing to see but darkness. They seemed to be picking up speed. The Doctor felt his ears pop. With no view outside, the seven people in the car began glancing at each other warily, avoiding eye contact.

"Ah, lifts. Another of those things that are the same everywhere in the universe," the Doctor commented.

To his surprise, one of the guards actually met his gaze, and seemed amused by his comment. It was the one Getl had left in charge - Khif, Getl had called her. She was wearing a Dark button.

"Tell me," the Doctor asked her. "Why do you hate aliens so much?"

"Who's said anything about hating? You've obviously been talking to Brights. Not all Darks are extreme xenophobes," Khif answered, taking him by surprise. Even though she looked like Getl, she sounded quite different, much less gruff.

"Good to know," the Doctor said. "If you don't mind me asking, what's the Dark agenda, then? If you're not an anti-alien party?"

"Well, the Preservationist Party originally began as an environmentalist movement. It's about protecting what's unique to us: our nature, our culture, our way of life. The Brights, on the other hand, they don't care if our age-old traditions disappear because they're not cost-effective. If we need to flood a nest to get more living space, it's only well and right, because petromites are just animals. If all small ranches go bankrupt because synthetic meat is cheaper, that's just progress. If..." Khif fell silent rather abruptly, eyeing the other guards, probably realising she'd got carried away. "Hm. You see what I mean."

"So, it's not as black and white as we first thought," Martha said thoughtfully.

"No, it's Dark and Bright," the Doctor noted. "Big difference. This is a cave world, after all, so there's nothing bad or evil about darkness. It's natural and familiar. Brightness is alien."

"Of course it is," Khif said, like she had never even thought it might be some other way. Most likely she hadn't.

"Not where some of us come from. I'm the Doctor, this is Martha, and that's Joseph. You're Khif, right?" the Doctor asked.

"Yes, but only to my friends," Khif declared, her tone making it clear that even though she didn't hate them, she was still a guard, and they were her prisoners. She didn't speak up again after that. The Doctor wondered if it was because she didn't want to, or because she was concerned it might undermine her authority over the other guards.

After fifteen minutes inside the rock, a bright, white light suddenly shone in through the lift's metaglass walls. It was only there for a passing moment, before the lift entered a building and came to a halt, but it was telling. It was sunlight. They'd reached the surface.

They were marched out of the car, and joined by the other group in a large, low hall, which was easy to recognise as a train station. There were only a few small windows in the stone walls, and they had green metaglass to filter the light.

The guards formed a circle around their prisoners, and escorted them through the hall, keeping the locals at a distance. They were taken to a platform, where an extremely sleek and streamlined train waited for them, gleaming a greenish silver in the soft light. It was a single car, with no locomotive in sight. The Doctor crouched to get a better look at the rails, or tracks, or whatever they might be, but one of the guards grabbed him by the collar and pulled him up.

"High-speed maglev, is it? Looks spiffy!" he tried, but the guard just glowered at him, waved a gun at him, and ushered him into the car.

The interior of their train was plain, but stylish, with low, green windows, just like in the station building. The seats looked very sturdy and were shaped rather like those in a racing car. Their lining, as well as the curtains by the windows, were in shades of silver and grey. Unlike the tram, the train had a driver, a middle-aged Khiandrian woman in a silver-grey uniform, which matched the surroundings perfectly. She nodded a wary greeting at them, and disappeared behind a door at the far end of the car.

"Sit down, stay still, and keep your hands where we can see them," Khif said, keeping up her tough guard act.

"How long is the trip going to take?" Martha asked as they settled in the seats.

"Almost four hours, unless the trains have evolved a lot," Jess answered.

"It's a tenth and a half these days," Khif said.

"About three hours, then. A tenth is about two Earth hours," Jess translated for them.

Smoothly and noiselessly, the train began to move. It glided slowly out of the station, but then, it started accelerating at such a rate that the passengers were pressed against their seats. It felt more like a rocket than a train. The Doctor leaned back his head, revelling in the rush of velocity.

"Just how fast are we going?" Brian spoke up. It was hard to tell if his voice was so soft because he was in awe, because he was wary of the guards, or just because of the strain of the g-forces.

"Just below supersonic speeds," Jess told him, grinning, seeming to enjoy the ride as much as the Doctor. "It's over two thousand miles from the City of Lights to the capital."

"Whew," Brian said, his eyes even wider than before.

All too soon, they'd reached their cruising speed. As they stopped accelerating, the feeling of great velocity was gone. The train moved perfectly steadily. The Doctor peered out of the window, but he couldn't make out much, and everything looked green, thanks to the filtering. It was a barren landscape, like Mars or the Moon. Something shimmering covered a good part of the ground, but he couldn't tell what it was.

The tenth-and-a-half trip turned out extremely dull. Apparently, Khif had decided that too much talk meant trouble. Every time the Doctor tried to speak up, to ask something, to marvel at the train, anything, she instantly told him to shut up.

They had already begun to slow down, when there was a muffled bang somewhere far away, and the train car shook around them, worse than the TARDIS on a bad day. The lights blinked off. Sets of five-point harnesses appeared automatically from their seats, tying them down securely. It felt like the train was skipping and sliding on its tracks. The Doctor was pretty sure it wasn't supposed to do that, because it would normally levitate just above the tracks, never actually touching them. Several guards had been standing up, and now, they stumbled. The Doctor thought he saw at least two of them fall, unable to get to their seats in time.

They were decelerating so fast that even the Doctor found it uncomfortable, squished between the seat and the harness so tightly that it was getting difficult to breathe properly. He wondered, worried, how the humans were holding up. He thought he could hear someone screaming, but the sound of tortured metal was so loud that it drowned everything else.

Finally, suddenly, the train came to a halt with a final, ear-splitting screech. Then, all was perfectly still and silent.


	5. The Surface

"Martha? You all right?" the Doctor asked, peering worriedly at her face.

Martha felt shaken and dazed, and a little nauseous, like she'd just been riding some crazy thrill ride at an amusement park. Other than that, she'd made it through the train crash without a scratch. "I'm fine," she answered him. "What happened?"

"Don't know yet. Obviously, we slowed down a lot faster than we were supposed to."

Martha looked around. The inside of the train car looked the same as before, except that it was darker. The only light in it was flowing in through the small green windows. At the front of the passenger compartment, at the foot of the wall separating it from the cockpit, two guards were lying on the ground, unmoving. "Everyone else all right?" she asked.

"Don't know that, either. We'd better find out," the Doctor said. He got up from his seat and scanned the room.

Martha copied his motions. As far as she could see, everyone who'd been sitting and strapped down was conscious and seemed more or less okay. Jess and Brian were leaning against each other, speaking softly. Joseph had his head between his knees, and Grant had placed a hand on his back. Khif had stood up, a frown on her face.

The Doctor had clearly come to the same conclusion as Martha. Turning his back to the seated people, he stepped to the aisle between the rows of seats, and started towards the two prone guards.

Several uninjured guards leaped up from their seats. "Where do you think you're going, alien?" one of them growled.

"We're doctors," the Doctor said, indicating himself and Martha. "We can help."

The guards still looked suspicious. No wonder, Martha thought. With two guards down, there were six guards and six prisoners. Much better odds than before, considering escape. Then again, they had no idea where they were, and no idea what the planet's surface was like.

"Please, trust us," the Doctor said steadily. "We're all in this together."

"Let them," Khif ordered the other guards. "But no sudden moves, you two. And everyone else remains seated."

Martha and the Doctor split up, both approaching one of the injured guards. The one Martha went to was lying on the floor in an awkward tangle of limbs, face towards the wall. He looked young, younger than Martha, and much shorter and skinnier. As Martha crouched closer, she saw that a big, nasty-looking bruise covered his forehead, and his neck seemed to be at a strange angle. She tried checking for breathing and pulse - or pulses, or whatever Khiandrians might have - but she found nothing, no signs of life at all. If Martha had had to venture a guess, she would've said the man had broken his neck, and died instantly.

"I... I think he's dead," she said softly.

"She's not," the Doctor announced from his patient. "But she does need help. Do we have any medical supplies? A first aid kit of some sort would be great."

One of the guards tossed him a white box, and the Doctor started going through its contents, most of which were little devices that Martha didn't recognise.

Khif came over to check on the guard Martha had examined. She sighed heavily. "He's gone, then. Poor Chal. It was his first assignment out of town," she shook her head and looked down. After a moment of silence, Khif got up, and walked to the cockpit door. The driver didn't answer when she knocked. She tried the handle, but the door was locked.

"I can help with that," the Doctor offered, and beckoned Martha to him and his patient. He placed a round device about the size of a matchbox on her palm. "Hold that over the broken ribs, and keep an eye on her breathing." Before Martha had time to ask him for a better explanation, let alone more detailed instructions, he'd bounced up and attacked the lock with the sonic.

Martha did her best to follow his orders, locating the obvious injury in the guard's side, and placing the little device over it. She almost dropped it, when it suddenly began to buzz. A few tiny lights blinked on its surface. The Doctor nodded at her from where he stood, and smiled encouragingly. Apparently, it was supposed to do that.

As she monitored the guard's breathing, which seemed to be improving by the second, Martha followed the Doctor and Khif's progress from the corner of her eye. The door was easily dealt with, and the two disappeared into the cockpit.

"She's not here! How's that possible?" Khif's astonished exclamation carried through the doorway.

"Left through that door, I reckon, probably as soon as we'd stopped," the Doctor's voice came in reply. "Must've been in on the plot, whatever that is. Let's see if I can make some sense of these controls..."

The guard Martha was tending to shifted, and moaned softly. "It's all right," Martha told her reassuringly. "You're going to be fine." The mysterious healing device had stopped buzzing, and the light's weren't blinking anymore, either. Martha figured that meant it was finished.

"Thanks," the guard whispered, drawing deep, shaky breaths.

A moment later, Khif and the Doctor stepped out of the cockpit. "It seems we've been hit by an EMP. There's probably been a bomb on the tracks," Khif announced. "An extremist attack, obviously. The train is completely inoperative, and the comms are down. The good news is, there seems to be a station not far from us. That means we're going out."

To her surprise, Martha saw the injured guard tense up and turn her head to stare at Khif, wide-eyed.

"Isn't there any other way?" another guard asked from behind them, almost pleadingly. "Wouldn't it be better to stay here and wait for help?"

"We don't know how widely communications are disrupted, or how big this attack was. We'll most likely be home sooner on foot. Don't be such grubs."

"What about him?" Martha asked, glancing at the dead guard.

"Him?" Khif repeated, looking puzzled. "That's not Chal anymore. His spirit has passed on. That's just meat, and carrying it around would only slow us down."

Martha gaped at her, taken aback.

"Different planet, different habits," the Doctor told her in an undertone.

She decided not to press her point.

"Well, what are you waiting for? Suit up!" Khif bellowed at the other guards.

They made a salute, and began pulling white parcels of some kind from under the seats. They tossed one to each of the prisoners, and took ones for themselves.

Martha unwrapped the lightweight bundle she'd been given. It looked more like a cape of flowing white fabric, with a pair of green goggles and a filter mask attached to it, than anything she'd call a suit. She saw Khif pull the hood over her head, and as the rest of the cloak settled over her, it somehow knit together on its own, enveloping her body. She stepped forwards to help one of the suits over the injured guard next to Martha. She was sitting up now, looking much better.

"Ooh, smart fabric! Very smart of you!" the Doctor exclaimed eagerly. He hung his suit in front of him, looking contemplative. "What are the conditions like out there?"

"Cold and windy, now that it's the dry season," said Khif. "In the wet season, we wouldn't even consider going out. The air is breathable without a mask, but only just."

"Hmm. Better safe than sorry," the Doctor decided, and let the fabric wrap itself around him.

Martha dressed in her suit as well. It felt strange, not as much like clothing as like stepping into warm water. It was quite comfortable, even the part over her face, although she found herself wishing the goggles came with clear glass instead of green.

Khif and the Doctor helped the injured guard to her feet. Martha was amazed to see that she could actually stand up on her own, even though she did seem to be guarding her side.

"I can walk without help, I think," the guard said, her voice a little hoarse. Her gaze met Martha's. "Thank you so much. If only all the alien-hating Darks had seen that!"

Martha smiled at her. "Maybe you can tell them about it."

"I will," she promised. "I definitely will."

Khif walked over to the door, and used an emergency handle to open it. The curtains fluttered as a strong gust of wind assailed the room, but Martha could barely feel it through the suit.

"I can trust you not to try and run away from us, right?" Khif asked the prisoners once they had all climbed out of the train car.

"Of course you can," the Doctor assured her. "As I said, we're all in this together."

They made their way down a concrete slope, from the elevated tracks to a narrow walkway next to them, and began walking. Khif took point, the Doctor and Martha came behind her, and the injured guard followed them with a fellow guard. The remaining guards seemed more suspicious than Khif, and stayed close to the rest of their prisoners.

As Martha glanced at the others over her shoulder, she noticed that all the guards were either looking down, or staring straight ahead. It was the view, she realised. They were afraid of it. That was why they'd been so reluctant to come out here. For people who spent all their lives in closed spaces, the open air must be as frightening as small tunnels were to her.

Martha, herself, felt glad and relieved to be outside after all the time they'd spent underground on two different planets. The landscape was barren and pocked with craters, but everywhere she looked, the ground was covered with some sort of plating. It looked vaguely familiar - solar panels, she realised. In the distance, she also saw a forest of tall pillars with rapidly spinning rotors: windmills.

"That's brilliant!" the Doctor enthused. "What a great way of using all this wide, empty space!" He had pulled off his hood, leaving his face bare. He was grinning widely. The weather didn't seem to bother him at all.

"Is it OK if I take this off, too, do you think?" Martha asked him, gesturing at the mask covering her face.

"Should be all right," he said. "It's just a bit chilly."

Martha grabbed at the strange, smooth fabric under her chin. There were no seams, but it gave way under her fingers, forming a flap, which allowed her to pull the hood off. A freezing cold wind instantly struck her face, making her eyes water, and the air smelled strange, but it was wonderful to be able to look at the wide open sky without the green filtering.

The sun had set during their train ride. The sky wasn't black, but a deep purple, sprinkled with unfamiliar stars. Martha saw two moons making their way across it. One of them looked like Earth's Moon, the other was smaller, full of details she couldn't make out, with an uneven edge - it must be one of the artificial moons. She wondered if one of those two was the Dungeon Moon. Looking ahead, along the tracks, she saw a low, flat stone building not far from them. It must be the station Khif had mentioned.

Soon, her cheeks were starting to grow numb with the cold, and the air somehow felt a little too thin. She glanced at the Doctor - he was still beaming, completely untroubled.

"Better cold tolerance," he told her.

She nodded, her teeth chattering, and pulled the hood over her head. She felt instantly warmer.

Once they'd reached the side of the station building, Khif went to the first door they saw. Before she'd as much as touched it, one of the guards cried out an urgent warning. "No, no! Stay away! Don't you recognise the station?"

Khif stepped back to take a good look - and then backed away some more, with a string of curses that didn't translate. "Keep moving," she yelled.

"What's wrong with this place?" the injured guard behind Martha asked.

"It's Nest Town Station! Suck it up and keep moving!" Khif repeated.

Nest Town - that was the place where the plague had struck. Martha noticed the Doctor had pulled the hood over his face. Of course, she didn't know if these surface suits would provide any protection from dangerous micro-organisms anyway. Then again, they hadn't even opened the door. Surely there was no risk at all.

They kept walking. As soon as they'd passed the station, they saw that there really had been a bomb on the tracks. There was a blackened and burned crater cutting them, at least thirty feet across. She shuddered to think what would've happened if the train had run into it.

"I doubt they wanted us to fall into that pit," Khif said, as if reading Martha's thoughts. "It was no accident we stopped where we did, right on top of Nest Town. Whoever did this, they were sending you a message: you brought it, you should suffer for it."

"Where exactly did the Plague come from, then?" the Doctor asked.

"I'm not sure anyone knows that," Khif answered. "The last I heard, they're still working on that."

"I could help. I've been around. Met a few plagues. Not that I mean that I might be carrying anything, mind," the Doctor said.

"I doubt they'll want your help, no matter what. You see how things are," Khif pointed at the bomb crater with her thumb.

They had been walking for what felt like at least an hour, when there was another building by the tracks. It was an angular block of stone slightly bigger than the TARDIS, with a door.

"Ah, an emergency exit," Khif said. She tapped at a point in the building's wall, and a small computer screen appeared. "In working order, too. Good," she added. She took a few minutes to make a call - audio only - to let the officials know what had happened and where they were, and then opened the doors to a large lift. There was just enough space for the six prisoners and the seven guards in it.

"We should be well past the dangerous area, and we'll be getting off at an upper level anyway, but better keep the suits on just in case," Khif said.

They stepped in, the doors closed behind them, and they were back inside, sinking rapidly deeper underground. As barren and unfriendly as the surface had been, Martha felt a little sad that they had to leave it behind so soon. Now, it would be all rocks and tunnels and dim green light again.


	6. Maze City, Central Holding Facility

There was a local hazard team waiting for them right outside the lift. They'd set up a tent around the doors, and everyone, the guards included, had to go through scans, one with the suit on, another one when they'd taken it off. The suits were all gathered in a sealed container. The Khiandrian authorities were clearly taking no risks.

Once the Doctor was finally allowed out of the tent, he found out they were in the first natural Khiandrian cave passage they'd seen so far. It had the round cross-section of a petromite tunnel, but the walls were covered in vegetation: short, pale grass, small flowers of different colours, with all sorts of pale insects flying and crawling about, none of them petromites - and most dominantly, there was moss, which was glowing a soft green light. There were no artificial lights about.

"So, is this is where the green light thing comes from?" Martha asked, gazing at the surroundings.

"Yes. And that's also why our days are twenty hours long," Jess explained. "Lumimoss has a twenty hour cycle, ten hours of light, ten of darkness."

There was a pleasant, fresh scent in the air, like a forest after rain. Where the Doctor could see bare rock, it was glistening with moisture, and in the background, there was the sound of dripping water. Of course! There were two main types of biomes in these tunnels: wet and dry. The dry caves weren't that different from caves on many other planets, except for the petromites. These wet caves were the really special thing.

Grant and Joseph were practically bursting with excitement and enthusiasm. The Doctor grinned at them, feeling just about the same. He stepped closer to the plants and stuck his face amongst them to get a better look at all the unique cave flora and fauna.

"If only I still had my camera!" Joseph complained. "Of course, they would never believe any of this at home even if I had pictures..."

"It's marvellous, isn't it? Look at that." Khif pointed at a creature that looked like a giant butterfly made entirely of clear glass, her big bad guard act cast aside once again. "It's a crystalwing. A rare thing, as are places as wild as this. To think that the Brights simply don't care... But, pretty as it is, this is not a pleasure trip," she said, sounding almost apologetic. "Back in line, all of you. We've still got many tunnel's lengths to go."

All too soon, they climbed down a ladder, moving from the fascinating green tunnel to a passage with much less wildlife. It was easy to tell they'd entered an inhabited area. There were doors in the walls, people passing by, and lamps in the ceiling. The tunnels had countless forks, and many stairs and ladders. Khif led them two more levels down, taking them to a large chamber, where a tram was waiting for them.

"This is the First Level of the city," Jess told them. "That's where we have the transportation, and most of the official establishments."

Jess had said early on that the City of Lights was more Earth-like than any other place on the planet. As the tram took them through Maze City, it was easy to see why, and it was also obvious where the name of the city came from. It really was a maze, a vast network of tunnels bustling with people. There were countless doors and windows in the walls, and caverns with tables, like little street cafés, and even a market - and most of this lay under a ceiling so low that the Doctor could've almost reached it by stretching out his arms and leaping up.

Finally, after all the hours they'd spent travelling, they reached their destination. It was yet another door in the cave wall, a sturdy-looking metallic one, with two guards in front of it. They saluted Khif, and opened the door.

Inside, they found themselves in a room that reminded the Doctor of the lobby of a hotel, except for all the guards lounging about. Khif talked with a person sitting behind a desk, and soon, the local guards stepped forth to take over from her troops.

"Thank you," Khif said to her former prisoners, and saluted them. "You could've run away, you could've caused us a lot of trouble, but instead, you helped us. I'm going to tell that to the higher-ups. Tell them to take it into account. I hope they'll treat you decently here."

The Doctor returned her salute as they were ushered into a lift, away from the lobby.

They went a few levels up to a long corridor with rows of doors in both walls. Their room was behind one of those, a large space with half a dozen bunk beds, and a few tables and chairs.

"Rest, or sleep, or whatever the likes of you do. Your trial begins tomorrow," one of the guards told them, and began to close the door.

"Wait!" Jess shouted after him. "I'm allowed to make a call, aren't I?"

The guard stopped. "Hm, yes, you are. Didn't think you'd want to. Come with me."

"Do we get calls as well?" the Doctor asked.

"Who would you call, alien?" the guard answered him with another question, clearly surprised. "It's only intraplanetary calls. I didn't think you had an ambassador here."

"No, we don't. But do we get to make a call?"

"Well, yes, you do. You'll need to wait for your turn, though."

The guard and Jess left, and the humans and the Doctor went on to explore their room. It was quite nice - there was plenty of space, the beds were soft, and they even had their own bathroom, complete with a small stone pool.

"This feels more like a dorm at a youth hostel than a prison cell," Martha noted.

"And how come they let us keep all our belongings?" Brian wondered.

"That's probably because we're technically not prisoners yet," the Doctor said. "We haven't even been officially charged with anything. We're just waiting. Besides, unlike lifts, prisons aren't the same everywhere in the universe."

"Seen a few of them before, eh?" Grant said. "So, Houdini, how are we going to escape this one?"

"I'm not in a hurry, actually," the Doctor answered, plopping down on the nearest bed and placing the soles of his trainers against the bottom of the bed above it.

He had already toyed with the idea of trying to escape - he was fairly sure he could manage it, one way or the other - but he'd decided against it. They had wanted to see the planet, and that was what they'd been doing. They'd wanted to help Jess, and they'd get a shot at that as long as they stuck around. Now, he only needed to figure out whether he should do something about all the big problems the planet had. None of those felt like fixed points in time. Everything was in a state of flux, and they were smack in the middle of it. The political situation, which seemed to be veering awfully close to civil war, wouldn't be easy to change, even if he hadn't been reluctant to meddle with it. The Plague, on the other hand, was something he probably could and should tackle.

"So, who are you going to call when it's your turn?" Martha asked him.

"Someone who knows something about the Plague," he said, placing his hands behind his head.

Grant glared at him. "How's that going to help us?"

"It isn't, but I'm curious." The Doctor smirked at the disgruntled caver.

"Besides, if we can heal their Plague, I doubt they'll be all that quick to send us to their prison moon," Martha said.

"There's that, too!" the Doctor declared, his smile even wider.

Fifteen minutes later, Jess returned, looking happy for the first time since her reunion with T'ig. "I called my sister," she explained. "Quite a call it was, too! She's not talking to our parents, either, not much, because she's very much a Bright - and she's got a mate, and a child - and -"

The Doctor had to leave the room in the middle of her eager account, since the guard was getting impatient. He took the Doctor back to the First Level, and there to a small, spherical room, with a control panel in the wall and two benches opposite each other.

"You have one hundredth," the guard announced, and closed the door, leaving the Doctor alone. If a tenth was two hours, then a hundredth would be twelve minutes, the Doctor reasoned. Not a terribly long time.

He had absolutely no idea how the communications tech here worked, but the controls didn't look all that complicated. He poked at the biggest button. A hologram of a young Khiandrian man appeared on one of the benches. The Doctor sat down opposite it.

"Greetings. I am the Network AI of the Central Holding Facility," the hologram stated. "All calls will be monitored and recorded. Who do you wish to contact?"

"Someone who can tell me about the Plague," the Doctor tried. "A researcher. A doctor."

"Please specify," the AI said. "The Nest Town Parasitoid Crystallosis Research Program currently has twenty-five members of staff."

The Doctor grinned at the monster of a name. 'Nest Town Parasitoid Crystallosis' - no wonder the media had decided to call it something more groovy. "Give me the one in charge," he told the AI.

"The current Head of NTPCRP is Gaer, daughter of P'ar, of Central Maze City."

"I wish to contact her, then."

"Very well. Please wait," the AI said, and disappeared.

The Doctor had to wait a few minutes, which he spent running his hands along the walls, trying to figure out where the holoprojectors were, and how they worked. Then, the AI reappeared, stated "Connection established," and disappeared again.

The hologram of a Khiandrian woman emerged on the bench. She looked very efficient and clinical, wearing a long, grey, figure-hugging robe with lots of pockets, and no button of any colour. Her light grey hair was close-cropped, with a triangular fringe.

"I'm Gaer. Who am I talking to?" she said, looking around as if she couldn't see the Doctor at all.

The Doctor sat down, and the woman's gaze settled on him. So, the holotech was built into the benches! "Hello! I'm the Doctor," he greeted her.

"Who?"

"Just the Doctor."

"You're an alien! Wait, you're one of the aliens from the City of Lights, aren't you?"

"Yes. Anyway, I don't have a whole lot of time. I just thought I'd offer you my help. You see, I know a lot about plagues. And I really mean a lot. About all sorts of epidemics, pandemics and interplanetary and interspecies disease. You don't know where that Crystal Plague of yours came from, do you? I'm fairly sure I could tell you."

"Actually, we do have a few ideas," Gaer replied dismissively. "Honestly, I doubt you could tell us anything we don't already know."

"You'd be surprised! Although I must admit I don't know anything yet. This Plague turns people to crystal, right?"

"No, not quite. How exactly are you supposed to be able to help us, if you don't even have the basic facts right? Not to mention that you're in custody, awaiting trial, suspected of all sorts of illegal activities."

"Please, trust me, I really do know these things. You've been working on this plague for, what, half a year, and you still don't know how to cure it. I'd think you'd accept all the help you can get!"

"And you know what I think? I think you don't know a thing, you've just come up with a clever plan to escape your captivity. No, 'Doctor'. Call me again after your trial, and next time, please try to come up with more convincing credentials than your word."

The woman vanished, the AI taking her place. The Doctor glanced at it, and a thought occurred to him. "Hm. You're the Network AI. That means you're a part of the local Grid, or Internet, or Datasphere, something like that?" he said thoughtfully.

"I do not recognise the references, but yes, I am the Network AI."

"Could you tell me about the Plague?"

"Only limited functions are available to detainees."

"Well, if that's how it is..." the Doctor muttered, and gave the controls a quick sonic prod. "So, tell me about the Plague."

"I have one encyclopaedia entry, 19 scientific publications, 1876 news articles, 3421 public conversations, and -"

"Let's start with the encyclopaedia entry."

"The Plague. Official designation: Nest Town Parasitoid Crystallosis," the AI recited. "Dubbed the Crystal Plague and the Diamond Death by the media. An infectious disease most likely of extraplanetary origin, capable of rapid adaptation to changing hosts and environments. Method of transmission: direct contact. Incubation period: none. Mortality: one hundred percent. Death usually follows within one cycle of the initial -"

Of course, the guard had to choose that very moment to knock on the door and announce that the time was up. The Doctor cursed himself for having been so stupid - he should've realised to ask the AI right away! He could just hear it explain that the usual causes of death were hypoxia and hypothermia, of all things, before the guard knocked again, and opened the door. The Doctor had little choice but to tell the AI to stop, and to follow the guard back to their room.

"Could've gone better, but at least I learned a few new things," he told Martha and the others. "And the more I hear, the clearer it becomes that this definitely isn't your basic Black Death sort of plague. Instead of buboes and fever, it comes with crystals and hypothermia."

"Hypothermia?" Martha repeated, frowning. "That doesn't make much sense, does it? How does it work?"

"I don't know," the Doctor admitted. "I don't think I've ever heard of anything quite like it. But whatever the progress of the disease is like, with an instant onset and a hundred percent mortality, it definitely sounds like a very nasty piece of work."


	7. The Halls of Justice

"What's going to happen tomorrow?" Brian asked Jess, breaking the silence that had lasted for some time after they'd finished talking about the Plague.

"I'm not entirely sure, to be honest," Jess answered. "It's been a long time since I left here, and I was hardly an expert on law back then. I guess that since our case is a crime against the entire planet-state, we'll be facing the Fifteen."

"Who's that?" Grant asked.

"They're... Sort of the jury, the judge and the prosecution, all in one. A highly esteemed group of the wise and learned. They're the highest court on the planet," Jess explained.

"What about the defence, then?" the Doctor said. "Do we just speak for ourselves?"

"We have the right to a spokesperson - I think they'd be called a defence lawyer on Earth. I've already asked my sister to find us one."

Jess didn't have much else to say on the subject, so they really couldn't do anything to prepare for the trial. All they could do was wait. Eventually, the humans decided to try and sleep.

According to Jess, Khiandria didn't have as clear a distinction between day and night as most other worlds, which wasn't surprising, considering what the place was like. Apparently, Khiandrians only needed a few hours of sleep, and although the "day", or the first half of a cycle, was generally more active than the other half, the city never really slept. All shops and restaurants were always open.

Night or not, Martha slept fitfully because of the strange surroundings and the nagging uncertainty of what the future held for them. She kept dreaming about Earth, about wide blue skies with wispy white clouds, wild moors, deep forests, and seemingly boundless oceans.

They only knew that "morning" had arrived when a guard showed up at the door. After a breakfast of tea and green porridge, which had a distinct taste of basil, of all things, they were marched to the Halls of Justice. The place was only a few blocks away from their prison.

In the huge entrance hall, decorated with stalagmites and stalactites bigger than any Martha had ever seen, they were met by two women. One of them could only be Jess's sister - aside from her curly, shoulder-length hair, they were almost identical. The other woman was bald, and there was something regal about her, the chiseled features of her face, and the way she stood, her head held high. To Martha's surprise, the guards allowed them to approach. Jess's sister walked straight to Jess, and grabbed her in a tight hug.

"Oh, how glad I am to see you! I only wish it were in different circumstances. Everyone, meet Khel, my big sister," Jess announced, beaming.

"Pleased to meet you all," Khel said, her smile mirroring Jess's. "And this is Neir," she motioned at the other woman. "An acquaintance of mine, and an experienced spokesperson. She's promised to help you on this case."

Jess walked over to Neir, and placed her hands on Neir's shoulders. Neir returned the gesture. Apparently, it was the Khiandrian equivalent to a handshake.

"We'll need all the help we can get. Thank you very much for coming," Jess said.

"You've got half a tenth before the first session begins," the guards informed them, and lead them to a space that felt like a conference room to Martha, with a long table and lots of chairs. Khel, who had no official purpose, wasn't allowed to stay with them.

Neir the spokesperson sat down at the end of the table, crossing her hands in front of her. "Now, we do not have much time, and I assume you don't know much. That doesn't matter, yet. The first session is mostly a ceremonial situation, an official reading of charges. The Fifteen have decided to make the entire trial a closed one due to the threat of extremist attacks, so you don't need to worry about spectators. Of course, it's broadcast all across the planet, but that's none of your concern. You're better off not thinking about it at all."

Martha found herself growing nervous as Neir spoke, even though the spokesperson was clearly trying to be reassuring. It just served to remind Martha how little she knew of what was going on here. What if they did something wrong?

"Simply do as the Fifteen say," Neir went on. "Speak if you're spoken to, otherwise remain silent. Stick to the truth. I'll signal you if what you're saying is deleterious."

Jess stood up, walked over to Neir, and said something to her in a whisper. Neir frowned at her, and stood up as well. The two Khiandrians withdrew to a corner of the room, to talk in very low voices.

"I wonder what they're up to," Grant said.

"Whatever it is, it clearly isn't our business," Brian snapped.

The hour passed surprisingly fast. Martha really didn't feel prepared when the guards opened the door to lead the defendants before the court. The courtroom, known as the Great Chamber of Justice, was every bit as impressive as the name suggested: a large, perfectly spherical room, with rows of benches circling the sides. At the moment, all rows except for the first one were empty. It was separated from the rest by a fence of tall stalagmites, which were carved into spirals, like a unicorn's horn. The first row was where the Fifteen sat. They were a solemn group, dressed in plain white gowns, ageless and androgynous.

In the middle of the room was the place of the defendants, which was a raised platform surrounded by pairs of rough, undecorated stalagmites and stalactites, like the jagged teeth of some huge monster. Even though courtrooms on Earth could be intimidating enough, this was on an entirely different scale. Standing on the platform made Martha feel like an animal in the zoo. She was glad that their trial was a closed one - she could only imagine how bad it would've been with all the benches filled with anti-alien Darks.

One of the Fifteen, a woman with her hair shaped into a stalagmite-like spike, stood up, and spread her arms. "We are the Fifteen, as are the Fifteen Pillars, the Fifteen Fangs in the Jaws of Justice. We are here to judge what is true, just and right," she declared in a ceremonial tone. When she stopped speaking, the hall was so silent that even a non-Khiandrian could've heard a pin drop.

The woman sat down, and another juror stood up to continue. The person was bald, and even when he or she began to speak, Martha couldn't decide whether they were a man or a woman. "We have heard many stories of what happened in the City of Lights yesterday. We have seen a considerable amount of evidence, and heard the accounts of Getl, daughter of Sarn, Head of Guard, Northwest District, City of Lights, and of T'ig, son of Sekh, of the City of Lights."

A third juror, a man with long, braided hair, went on. "We are here to discuss those events, and the related crimes of these six people: Jess, daughter of Jem, formerly of Chute Town, and the aliens Brian Ford, Grant Richardson, Joseph Stratton, Martha Jones and John Smith, also known as the Doctor, from planets whose governments we do not have diplomatic relations with. They are represented by the honourable spokesperson Neir, daughter of Nael, of Maze City North. Is there anything you wish to say before we begin?"

"Indeed there is, Honoured Ones," Neir said, her voice loud and clear. She was standing just outside the platform, and walked around it slowly as she spoke. "I would like to note that, as you said yourself, not all of those I speak for are Khiandrian. These five aliens know nothing of Khiandrian laws. They never even asked to be brought to this planet, but were brought here by Jess, daughter of Jem. Because of this, on her behalf, I suggest she should be held in full and complete responsibility for everything that has happened."

Her words seemed to raise a commotion amongst the Fifteen - they murmured, their stoical expressions faltered ever so slightly, and their heads turned as they exchanged glances. Martha saw the other humans and the Doctor look from Neir to Jess, clearly as confused as she was. Jess had a strange, defiant glint in her eyes, and Neir's thin lips were curved in the slightest of smiles. This must've been what they'd talked about in private. What were they up to?

A fourth member of the Fifteen stood up. "What you suggest could have serious consequences," he said, fixing Jess with his gaze. "Jess, daughter of Jem, do you truly wish to become the sole defendant in this case, as your spokesperson has proposed?"

Jess stood up, a very determined look on her face. "That is my wish, Honoured Ones," she declared.

"What? Wait!" the Doctor exclaimed. He had leaped to his feet, and Martha could see every eye in the hall turn towards him. Neir glared at him, shaking her head and gesturing with her hands that he should sit down.

"John Smith, also known as the Doctor, whose heritage and home are unknown to us - what do you have to say to the Fifteen?" said the previous speaker.

"Honoured Ones," the Doctor began, ignoring Neir's attempts to catch his attention. "I would note that as alien as I am, it was my ship that allowed us to enter the City of Lights, and that I willingly offered to give Jess a ride. Also, once we were here, I specifically asked her to show us around. Thus, I don't see how she could be accused of everything alone. These humans, they've just been hanging around, but me, I'm as involved as she is."

Martha stared at him, baffled. Of course, she didn't want Jess to take all the blame, either, but it had seemed to her that the Khiandrians had known what they were doing. The Doctor, on the other hand, was clearly just improvising.

"The Fifteen have heard the request of the alien known as the Doctor. We will now discuss these things amongst ourselves. You shall be summoned again once we have reached a conclusion."

For the time being, the defendants and their spokesperson were escorted back to the conference room.

"What do you think you're doing?" Martha hissed at the Doctor as soon as they were by themselves. "You want to land yourself in prison and leave the rest of us stuck here?"

"I'm more interested to hear what Jess thinks she's doing," he said, turning to look at the two Khiandrians. "Can you really take the blame for everything, just like that?"

"Not just like that. It's a very old thing we were taught about at school, and I remembered a similar case from when I was young. That's why I asked Neir about it," Jess said, without a hint of regret.

"And I approved, even though it's not exactly the most prudent course of action," Neir said. "You see, since the earliest days of our history, a mother has had the right to take the blame for her children. When Khiandria was a feudal monarchy, that right was extended so that someone of high status could do the same for their subordinates, and a form of those laws still exists. Now, since you're aliens, and Jess could be regarded as having higher status and being in charge of you, it's possible that they'll accept what we've proposed. Of course, with the current xenophobic atmosphere, that's far from certain, even though the Fifteen should be above such things."

"If it does work, what happens, then?" Brian asked, staring at Jess like he was afraid she'd disappear if he turned his gaze. "If you do get what you asked for, what happens to you - to us?"

Jess smiled warmly at Brian. "They'll accuse me of everything, charge me with breaking the quarantine laws, trespassing, possibly even treason. If I'm found guilty, they may go for the worst possible punishment: exile from the planet. For life."

"Oh," Martha said, finally realising why Jess had done what she'd done.

The Doctor raised his eyebrows at Jess. "So, you get exiled, and we get no punishment at all?"

"Not a bad deal, don't you think? I would miss Khiandria terribly, but it doesn't really feel like home anymore, anyway."

"You would leave behind all this," Grant gestured vaguely at the cave around them, "Just to protect us?"

"Oh, no. Of course not. I'd leave behind all this to stay together with Brian," Jess said.

"But it's a huge gamble," the Doctor remarked. "Even if you got what you asked for, they could send you to prison for life instead of exiling you."

"That's entirely possible, yes," Neir admitted.

"You trying to be all chivalrous definitely didn't help," Jess noted, glaring at the Doctor.

"If you had explained this to us in advance..." the Doctor began.

"Would you have let me do it, then?"

"Well... Most likely not. I'm all for people taking responsibility for their misdeeds, but no one should have to pay for something they didn't do."

"It's not quite so simple," Neir said, and launched into a complicated explanation of Khiandrian legal practices, traditions, and philosophy. The Doctor leaned towards her, asking a question every now and then, clearly eager to understand it all better.

It wasn't exactly exciting talk, complicated and full of strange legal terms, but still, Martha was a bit ashamed of herself when she found herself yawning, suddenly feeling all sleepy. It was only when she noticed that Neir was yawning, too, and Jess was nodding off, that Martha realised something wasn't quite right. Unfortunately, by that time, she was so overwhelmingly tired that before she managed to say anything, she slumped against the table, fast asleep.


	8. Unknown Location

Something was very much not right. Everyone seemed to be falling asleep. The Doctor felt woozy. There had to be something in the air, something insidious, invisible, odourless, and otherwise hard to notice. It was strange he hadn't spotted it earlier, since Time Lords were very sensitive to such things, but then again, so were Khiandrians. He could feel it now, playing havoc with his biochemistry. He tried to fight it off, but it was difficult, since he'd already inhaled a fair amount.

He stumbled to his feet. Everyone else was unconscious, and they didn't react when he tried to rouse them. He made his way to the door, leaning on the walls and the backs of chairs, calling out for help. The door was locked, of course.

He heard a soft thud behind him, and turned around just in time to see a slim figure dressed in black from head to toes, wearing a gas mask, drop on the table through a hole in the ceiling. Another such figure was already standing on the floor next to the table, gun pointed at the Doctor. There was a zap, and he felt the familiar jolt of a Khiandrian stun gun, which sent him sprawled on the floor, face-down.

As soon as the Doctor had regained some control over his limbs again, he tried to get up, but a heavy weight landed on his back, pinning him down.

"This one's stubborn, isn't he?" a mocking soprano spoke up above him.

The weight disappeared, and he felt himself being hauled up from the floor. He tried to struggle, but his coordination was still off, his movements listless.

The dark figure hung him by the collar. She was so short that his knees still touched the ground, but she clearly had no problem at all holding his weight. She stared at him, masked face tilting from one side to the other. "What do you know. You hear that?" she said to her partner. "Double heartbeat. This is our boy."

"I wish we could take the whole bunch of them," the other masked figure, a man, spoke up. He was looking at Martha's motionless form. "The aliens, the traitors..."

"We have our orders," the woman declared.

"These contrast gigs -" the man began.

The woman hissed sharply. "Not here!"

By this time, the Doctor had gathered his wits somewhat, and opened his mouth to protest against this random assault, but he didn't get out as much as a squeak. The Khiandrian holding him swung a heavy fist at his face, and before he knew it, he was every bit as unconscious as everyone else.

**********

When Martha woke up, everyone was speaking in gibberish. There were several Khiandrians in the room, talking in animated voices, but their speech was a series of clicks and sneezes and melodious vowels that made no sense to her. Around the table, she saw the other humans stirring, all groggy and confused. The Doctor was nowhere in sight. She looked around, and could see, among guards and other unknown Khiandrians, an angry Jess, a serious Neir, and Jess's sister Khel, who looked very unhappy, but there was no sign of the Doctor at all.

"What's going on?" Martha asked.

The Khiandrians turned to stare at her, looking puzzled. Khel said something, but again, Martha couldn't understand one word of it.

"I don't get it," Jess said, in English. "We could understand each other just fine before. I didn't even think about it then - obviously, you don't know Khiandrian, and they don't know English. Why did we understand each other before? Why's it changed? As if this wasn't enough of a mess without that!"

"It's the Doctor," Martha said, with a sinking feeling. "The TARDIS was translating for us, somehow, and it works through him. What's happened to him? Where is he?"

"Damned if I knew!" Jess groaned. "He's gone. Someone drugged us and took him - but the guards refuse to believe that it was an attack, and not some sort of an alien ploy!"

A man in a guard's uniform addressed Jess, who scowled at him, but translated the words to the humans. "They're moving us to another, more secure room."

The secure room was a small one, with uneven walls of bare rock, and only a few stone benches for furniture. It could've been a cave chamber somewhere on Earth, and it felt more prison-like than anything Martha had seen so far. Neir wasn't allowed to stay with them anymore.

"Don't they have CCTV here? I mean, security cameras, or other surveillance equipment and such, so they could find out what really happened?" Martha asked Jess, leaning against the cold wall.

"Of course they do. This should be one of the most secure places on the planet. Whoever did this was somehow able to turn everything off - not to mention that they were able to introduce a gas of some sort into the room without anyone noticing. All in all, I think it's obvious they must've had an inside accomplice," Jess said.

"And why did they take him?" Martha went on. "What could they hope to gain? He only wanted to help everyone!"

"They're probably making a point, just like the people who attacked the train," Jess suggested.

"But why only him, then? Why not all of us? We're as alien as he is!"

"Maybe because he's different from the rest of you, and he's clearly given the impression that he's your leader. Maybe because he stood up for me in front of the Fifteen. I don't know, really," Jess said sullenly, and slumped to sit on one of the benches. "Honestly, I don't understand any of this any better than you do. When I left home, violent attacks like this were considered a thing of the distant past."

They must've been waiting for hours, Martha's worry growing steadily, when finally, the door was opened. "You've been summoned by the Fifteen. Come," the guard said, in plain English. Martha wasn't sure what that meant, but she decided she could at least be certain that the Doctor wasn't dead.

Even though she now understood the language, it took her a moment to actually grasp the meaning of the guard's words. She'd almost forgotten about the trial, and it felt like something that had happened a very long time ago. Still, the Great Chamber of Justice was just like it had been before, and Neir and the Fifteen were waiting for them.

One of the Fifteen rose to speak, a tall woman who hadn't spoken before. "The Fifteen have come to the conclusion that Jess, daughter of Jem, formerly of Chute Town, who asked to be held responsible for the possible crimes of her alien companions, will be granted her wish. Thus, no charges are pressed against the aliens Brian Ford, Grant Richardson, Joseph Stratton, Martha Jones, and the currently absent Doctor, regardless of their actual involvement in the events."

Currently absent - was that all the notice they took of what had happened? Martha thought, outraged.

A second juror stood up and went on. "Jess, daughter of Jem, formerly of Chute Town, is charged with serious violations of the Quarantine and Travel Laws both in 4358 and in 4381, as well as bringing a group of aliens to Khiandria on the 22nd cycle of the third season in 4381, in direct violation of the Emergency Law, thus trespassing on Khiandrian soil, and causing risk to all local life - an action which, under the current circumstances, the Fifteen consider an act of treason. The trial will recommence tomorrow, at the first tenth. The aliens' presence will be required as well, as they remain important witnesses."

A third juror stood up, and spread her arms ceremoniously. "What has been spoken and decided here today has been right, just and true. The Fifteen have nothing more to say."

Once the Fifteen had filed out of the room, the guards showed up to take the prisoners away - except that they found out they weren't prisoners anymore.

"We're only here for Jess, daughter of Jem," one of the guards announced. "The rest of you are free. Keep in mind that if you do anything illegal, she won't be able to protect you anymore."

"What about that attack, then? The Doctor getting kidnapped and all?" Martha asked incredulously. "I thought you suspected us for it."

"No, not anymore. We received a message from the Deep - they're a Dark extremist group. They announced that they've captured your friend. Took him where he belongs, that's what they said. Rest assured, we're doing our best to find him."

"But what're we supposed to do now? We hardly know anyone here, and half the city wants to lynch us, or kidnap us, or blast us to bits!" Grant complained.

"You should've thought about that before you came here and started breaking our laws," the guard said condescendingly.

Neir glared at the guard even more disdainfully, as if he were barely worthy of her attention at all. "Don't worry," she told the humans. "Khel is waiting for us in the entrance hall. You're not without friends here."

**********

When the Doctor woke up, he was entirely convinced that he was still on Earth, in Lechuguilla Cave, with a concussion. He was lying on a cold stone floor, feeling dizzy and a little queasy, with a terrible headache.

He opened his eyes, and blinked, and raised his hand to shield them from the dazzling white light all around him. Weird. By the time his eyes had adjusted, he'd come to realise that the headache was on the wrong side - and then, he remembered it wasn't a fall to a chasm but a sharp blow from a masked Khiandrian that had caused it.

The tunnel he was in was clearly another old petromite tunnel, round and maybe fifteen feet in diameter. It was entirely lifeless, and no wonder. The light pouring from the rows of lamps in the ceiling was so bright that no Khiandrian life form would stand it. The tunnel seemed to go on in both directions, but it curved so that he couldn't see very far. He'd obviously been kidnapped, but why had he been left alone? This didn't look like a cell. Where was he?

He got up. The surroundings spun a little, but the nausea was already abating. He followed the curving tunnel. Not far ahead of him, the lights came to a sudden stop, like a solid wall of darkness. He half expected it to feel solid, too - but before he had even reached it, he ran into an invisible barrier. A force field. He saw a control panel in the tunnel wall, but it was on the wrong side of the force field.

He turned around and tried the other direction. There, too, he found a wall of darkness, but there was no force field blocking the passage. Beyond the sharp change in lighting, the tunnel went on unchanged. He soon noticed that it wasn't actually dark, just dim, with the usual green lights.

After some hundred feet of walking, he reached a big, round room with a khirindal. It seemed abandoned. There was something on the ground right in front of him, a pale little thing. He crouched to get a better look. It was a petromite, but it wasn't glowing. Instead, it had a strange, milky sheen. He bent even closer, and poked a finger at it.

He had barely even touched the petromite, when it crumbled to a pile of white crystal dust.

With a startled cry, the Doctor pulled back his hand and stumbled backwards. He finally realised what he'd been looking at, and he knew where he was. How come he had been so slow? It must've been the combined after effects of the poison gas, the stun gun, and the hard punch to his poor head.

He could only hope he was lucky, or immune. Preferably both.

He headed away from the khirindal, choosing a tunnel which seemed parallel to the first one. Like he had expected, he soon found a brightly lit area, intersected by a force field. He figured the lights were an extra precaution, while the force field was the actual, impenetrable safeguard separating the quarantine zone from the rest of the world.

He poked and prodded at the force field, first with his hands, then with the sonic screwdriver. It was no good. He needed to reach the controls, but he couldn't, with the force field between him and them. Of course, that was the way it had to be, to keep anyone from escaping. The people who had put these obstacles here had known what they were doing.

He realised his right forefinger felt a little strange, the finger he'd touched the crystallised petromite with. He looked at it under the bright lights.

On the tip of his finger was a tiny, glimmering speck, like a snowflake or a small chip of ice. It felt a little like melting ice, too, or maybe the opposite, like a point where the temperature had somehow dropped to subzero, his fingertip starting to freeze. The tiny crystal looked like it might come off easily, but of course, no matter how he tried to wipe it against his pant leg and the cave wall next to him, it wouldn't budge. He even tried a few different sonic settings on it, to no avail.

He stared at his finger, a chill running down his spine. He was neither lucky nor immune. He'd been marked by the Diamond Death.

* * *

**Author's Note: **I bet everyone saw that one coming - I did say there was going to be whump, didn't I? ;)


	9. Nest Town

Neir departed their company at the door of the Halls of Justice, promising to let them know if she heard any news about the Doctor. Jess's sister took Martha and the other humans to her place, which was a tram ride and two flights of stairs away from the Halls. Being among the Khiandrian crowd felt even more intimidating than before. Some of those suspiciously staring locals might well belong to the organisation that had taken the Doctor, or to some other anti-alien group. Martha felt relieved when they'd finally reached their destination, and Khel closed the door of her apartment behind them.

"I'm an architect and I mostly work from home, so you don't need to worry about disturbing me or anything. My mate, P'atl, is on an assignment on the First Moon, and won't be back until the day after tomorrow," Khel told them. "And here's our son, Taer." Khel pointed out a small, shy figure hiding behind a drawer, peeking at the strangers curiously.

Unlike T'ig's place, which had clearly been inspired by traditional cave dwellings, Khel's home looked very modern to Martha. It was new and shiny, all white walls, glass, crystal and mirrors. The best thing was, all the lights weren't green. There were almost as many different colours as there had been in the City of Lights.

Khel sat her visitors in her dining room, and brought them soup, which was, like all food Martha had seen here, greenish, with a strong scent of herbs. Martha twirled her spoon in it, wondering if there was meat in it, and where it came from. She really wasn't the least bit hungry.

"These Deep," she asked Khel. "Who are they? What do they want?"

"They're a very conservative group even compared to other Dark extremists. They're royalists. They'd want to return to the old times, to have a Queen on the throne again instead of an elected Chairperson. Of course, back in the 'good old days', there were hardly any aliens on the planet. They believe it's the aliens' fault that we abandoned the old ways and switched to a more egalitarian system - as if it were a bad thing," Khel explained rather heatedly.

"Are they the same group who planted the bomb on the train tracks?" Martha said.

"No. A group called Obsidian confessed they were behind that. They're anti-alien above all else."

"Just how many of these groups are there?" Brian moaned.

"I doubt anyone knows," Khel said, shaking her head. "It's not like they're officially registered anywhere. There are half a dozen big groups, both Darks and Brights, and countless small ones. Of course, most of them aren't this violent. Obsidian and the Deep are amongst the most infamous ones."

"Do you think the police - I mean, the guards, are going to find the Doctor?" Martha asked softly.

Khel grimaced. "I don't know. People have been captured before - known leaders of the opposite party, aliens, even reporters who've stuck their nose in the wrong place. Sometimes they're found, sometimes not. Sometimes they're only found when it's too late. The problem with the guards is, some of them are anti-alien themselves. I don't know how hard they'll be working on this case."

"Then we have to find him ourselves," Martha declared.

"But he could be anywhere on the planet - if he even is on the planet anymore," Khel said.

"We have one clue," Grant noted. "They said they've taken him where he belongs. What do you suppose that means?"

"They don't know his homeworld, and they wouldn't be able to send him there anyway, but maybe they'd go for off-world? Or the Dungeon Moon?" Martha suggested.

"Space travel is strictly regulated, as you well know," Khel said thoughtfully. "I can call P'atl. She's a pilot, and she has lots of contacts, reliable ones, at the spaceport. She'll probably be able to tell whether that's a possible scenario."

"P-ahl..." Joseph tried to repeat the name, not quite getting there. "I thought that was the name of your mate?"

"Yes, it is."

"But - a woman?" Joseph said disbelievingly. Martha smirked at his confusion. Of course a man from the Sixties would be baffled by the idea of same-sex marriage as a perfectly ordinary thing.

"Is your son adopted, then?" Brian asked.

"Adopted? Why?" Khel said, looking as confused as the cavers. "Anyway, I'd better make that call right now. We may be short on time, after all. Please, finish your soup."

Martha ate mechanically, not tasting a thing. She was glad they had Khel's help, and that of her mate, when it came to space travel. However, if the Doctor was still in these caves, that wouldn't be enough. They needed more help, more allies. If only they knew more local people!

Martha could think of one person who might be able to help. When Khel returned, Martha asked if she could make a call, too. Khel took her to what she called the local "terminal", a corner of a room with two chairs facing each other, and a control panel in the wall. She guided Martha through the process of making a call, which included sitting on a chair and talking to the House AI, who was a hologram that looked like a pretty, young Khiandrian woman.

Martha asked the AI to contact Khif, a guard from the City of Lights. Unfortunately, the AI announced that Khif wasn't available at the moment. Martha left her a message, explaining the situation, and asking her to call back as soon as she could.

"How come you're this advanced, but don't have mobile phones?" she complained to Khel.

"Mobile phones?"

Martha showed Khel hers. "Little phones which you keep with you, so you can be reached at all times."

Khel looked appalled. "At all times? Who'd want that? Sure, guards and paramedics have such systems, but they only use those when they're on duty. I'm sure this Khif will call you back soon."

In the meantime, Martha could do nothing but wait and think. 'We've taken him where he belongs.' What could that mean? Where else would an alien belong than space? She tried to imagine a similar situation on Earth. A lab, maybe? A zoo? Did they even have those on Khiandria?

Eventually, Khif did call her back, and Martha went through some of her ideas with the guard, but she didn't have any insights to offer. She wasn't overly optimistic about her ability to help, either. "I'm not a terribly high-ranking person here, but I'll do what I can," she promised.

"That's all I'm asking. Thank you," Martha told her.

"He's a resourceful man," Khif said. "I'm sure he'll be fine."

**********

The Doctor kicked at the fifth force field and groaned in frustration. He'd been going through all the tunnels in the area, but so far, he'd had no luck. The crystal growth was creeping slowly along his finger. So far, it only seemed to be covering the skin, which he could still see underneath the translucent surface. It felt freezing cold, and whenever he tried to bend his finger, sharp pains stabbed at it, like a million tiny needles pressing into his skin. He wondered if cutting it off would be a way to stop the progress of the disease. Surely not. Surely the Khiandrians would've thought of that already. Whichever the case, he wasn't going to try it. He was rather fond of that finger, and he wouldn't be able to grow a new one just like that.

He turned his back to the force field and moved on. He'd seen many abandoned cities and destroyed towns before, but the fact that this one was an underground labyrinth made it eerier than most. The huge, echoing chambers, the empty tunnels with countless doors, the dark passages and holes here and there, all of it perfectly silent except for the slightest hum of lamps and force fields - it was like a thing out of someone's nightmare.

He spotted what looked like a pile of clothes on the floor, and stopped to take a closer look. There was crystal dust on, in and around the clothes. The Doctor shuddered, and kept moving.

He came across several more bodies - if they could even be called that - as he went on looking for an exit, climbing up and down stairs and ladders to different levels. Things only seemed to be getting more and more nightmarish. Once, he met a body that hadn't crumbled to dust. It looked more like a statue than anything that had once been alive. The Doctor could see no skin beneath the layer of crystal, just more translucent, white material. Even though the facial features were blurred, the expression was unmistakable - the lips were curled in a grimace of pain, the eyes screwed tightly shut. The Doctor gave the poor soul a wide berth, but still, the crystal figure fell apart as he walked past it. Maybe it had been the slight vibration caused by his steps, or the tiniest wisp of wind. He glanced at his infected hand, swallowed, and walked on.

After hours of fruitless wandering through tunnels which either ended in force fields or were literal dead ends, he found himself in a wide passage with lots of doors, and tram tracks on the ground. He was on the First Floor. He followed the tracks in the direction which he suspected to lead out of Nest Town. Like he had known to expect, the tunnel ended in yet another force field - but unlike in every other tunnel, this one had a control panel on both sides.

He fiddled with the controls for some time, using his good left hand and the sonic. His right had was well nigh useless now, covered in translucent crystal from fingertips to the wrist. Finally, with a faint hiss, the force field dissipated.

Beyond the force field, the bright lights went on, revealing a short stretch of tunnel, and then, a white wall cutting the corridor, with a small door in it. The Doctor gave the inner control panel a poke to close the force field behind him, and walked over to the white wall. The door had controls similar to the force fields', with a number pad and a fingerprint scanner. He dealt with those easily, and stepped through the door.

The door led to what was clearly a decontamination room. A little too late for him, but at least he could make sure he wouldn't spread the Plague. He managed to find a discarded smart fabric suit, and once he'd dressed in that, he went through the whole set of safety measures, including a shower with something that most likely wasn't water, and a quick bath of some sort of radiation.

He walked through a dressing room and an outer door, which opened into a sizeable cave chamber. There was a compound of small buildings in it. They were simple, round-edged blocks of plastic-like material. Somehow, the place had the air of a dwelling that had been supposed to be temporary, but had turned long-term: the buildings were like the barracks at a construction site, but there were tracks trodden into the cave floor between them, and a few of them even had little gardens.

Not far from the Doctor, a young Khiandrian, barely older than a teenager, was walking hurriedly towards one of the buildings. He was wearing a gown with lots of pockets, like the one Gaer, the Plague researcher, had had.

"Hello," the Doctor called out. "I'm lost, and I'm afraid I've got a bit of a Plague problem, too."

The young man froze, and turned to face the Doctor, wide-eyed in surprise. "Hello there," he greeted a little warily. "You've come to the right place, then, I guess. This is the Nest Town Parasitoid Crystallosis Research Centre. Although, if by problem, you mean infection, then there's very little we can do for you."


	10. Four Hours

Martha was in the backyard with Khel's son and the cavers when they heard the news. The "yard" was an enclosed space, a cave chamber larger than any of the actual rooms of the apartment. The floor and a part of the walls were covered in mosses and grasses. They'd been watching Taer climb around the chamber, even across the ceiling. Brian had tried to join in, but his skills were no match to the young Khiandrian.

Khel ran to the backyard, looking like she'd just seen a ghost. "Your guard friend just called to let us know that the Doctor has been found," she said. Her tone made it clear that something was badly wrong. "I'm sorry. It was too late."

"I - I don't understand," Martha stammered. "He can't be dead. It's just - it's not possible!"

"He's not, but within a cycle, he will be. He has the Crystal Plague."

Martha remembered Khif's words after the train crash - 'They were sending you a message: you brought it, you should suffer for it.' The extremists had said they'd taken the Doctor where he belonged. "They took him to Nest Town," she said softly.

"I'm afraid so," Khel said.

"Can I see him? Where is he?"

"At a research centre, just outside Nest Town's West Entrance. I've already looked up a tram."

Less than an hour later, they, minus Taer, were standing in a white isolation room with bright, white lights. The room was split into two sections by a transparent force field, the larger part of it only accessible through an airlock door in one of the walls. It was furnished with a computer screen set into the back wall, a small table, and a low bed, where the Doctor sat. He didn't really look mortally ill, just a little paler than usual. He stood up and waved at them with his left hand. His right arm hung limply by his side, the hand covered by a strange, translucent crystal growth, which seemed to continue under the cuff of his shirt.

"Doctor," Martha said, pressing her palm against the invisible wall between them. It felt to her as if he'd been gone for far longer than some hours, no less so because those hours had changed the situation completely.

"Martha! Cavemen!" he greeted them. Was she imagining it, or did his smile look a bit strained? "How nice of you to come."

The three cavers returned his greeting sombrely. The way they were acting - a little awkward, unsure of how to behave toward the Doctor - was something Martha had seen before, whenever people were faced with someone who was incurably ill.

"So, how was the trial?" the Doctor asked, his tone casual.

"Jess got what she wanted. We're free, and she's still in custody, facing a load of charges," Brian told him glumly. "Does - does that hurt?" he asked, eyeing the crystal covering the Doctor's hand.

"A little," the Doctor admitted. "And it's really cold. What T'ig said, that the Plague turns you to crystal, that wasn't entirely right. At first, it only covers the skin. It soaks up body heat, and it may even be able to utilise other easily available forms of energy. It's very adaptable. Quite an extraordinary thing."

"Soaks up body heat - so, hypothermia as a cause of death?" Martha said.

"Yes. Either that, or suffocation, when the growth wraps itself around the chest or over the face, preventing normal breathing. Once the host is completely covered, the organism starts feeding on tissue," the Doctor went on, speaking in a detached, even fascinated manner, like he was giving a lecture about some curious natural phenomenon, instead of a deadly disease that was trying to eat him alive. "Eventually, it'll turn the entire body into a mass of fragile crystal, which falls apart easily. The dust goes on to infect others - it spreads easily and is highly contagious."

Martha placed both her hands against the force field, feeling so appalled that it made her nauseous. The Plague didn't just kill its victims. It obliterated them. "How long?" she breathed.

"Well, for Khiandrians, it takes about a cycle, but I'm a little more resilient." The Doctor brought his left hand to his right shoulder and felt it gingerly, apparently checking how far the crystal growth had progressed. "It's been four hours since I got infected, and it's taken about ten percent of my total body surface area," he said. Martha recognised the measure usually used when talking about burns. "So, that'd give me about thirty-six hours before it's covered me entirely. Two tenths short of two cycles. Of course, that's just an estimate, and there are lots of factors I don't know. Anyway, Time Lords can deal with hypothermia and lack of oxygen better than most other life forms."

"Besides, you'll be able to cure it, right? Stop it before it even gets there?" Martha said, hearing a hint of desperation in her own voice.

"Well, it's not going to be easy, but of course I will. I'm very clever, after all." He stepped closer to the force field, raised his eyebrows at the humans, waved at the cavers with his good hand, and brought his thumb and the other fingers together in a gesture indicating talk.

"Huh?" Grant said, puzzled by the Doctor's mime.

"Keep talking," Martha whispered. She had no trouble interpreting him. He was afraid they were being listened to, and wanted the cavers to cover whatever he was about to say.

"I do hope you'll fix it soon, so that you can finally take us home," Joseph said, his voice a little louder than normal.

"Yes, the caves are great, but I miss home, too," Grant joined in.

"No - not when Jess is still in prison!" Brian exclaimed.

While the three men went on arguing loudly, the Doctor leaned against the force field to talk right into Martha's ear, his voice so low she could barely hear him. "Something's not right here. Imagine you were a Khiandrian Plague researcher right now. What would you do?"

"I don't know," Martha said, surprised by the question. "I'd be curious, I guess. Hopeful, even, because you're a unique case, of a different species. I'd want to run all possible tests, and..."

"And that's it, Martha Jones. That's exactly it. They're not curious. I was completely expecting to become their guinea pig. Instead, they don't seem interested at all, and they won't let me do any research, either."

"What?" Martha said incredulously. "Why?"

"I'm practically a prisoner here. It might be just because I'm an alien, but I don't think so. I think there's something dodgy about this all. Since I'm stuck here, I need you to find out what that is."

"I will," Martha promised.

"I'll get you back home, if it's the last thing I do," the Doctor suddenly raised his voice to comment to the cavers' moaning. "In the meantime, I want you all to be very careful. Whoever took me might strike again."

"They're called the Deep," Grant said. "The extremists that took you, that is."

"Do any of you remember anything of the assault?" the Doctor asked.

"Not really, no," Joseph said.

"We were all fast asleep," Martha said. "Do you remember something, then?"

"Yup. I had a little talk with a man and a woman in black. Well, they had a talk, and I listened in. They were Darks, obviously, all anti-alien," he said, and made a discreet gesture at the cavers that they should go on talking again. "And," he went on in a whisper to Martha. "There's this detail I overheard. I think they were working for someone else. I thought the word was 'contract' at first, but it wasn't. I'm pretty sure it was 'contrast'. It might mean something."

No matter how many mysteries he wanted her to solve, Martha would've preferred to stay with the Doctor all through the local "night", until the trial. Unfortunately, the young Khiandrian woman who had showed them to the Doctor's room returned barely half an hour after they'd arrived, and asked them to leave, claiming that the Doctor needed rest.

The Doctor rolled his eyes at that. "That's exactly the one thing I don't need," he commented. "But, I guess you should be going, then. Bye. Say hi to Jess from me." He raised his eyebrows at Martha. "And don't forget what I said. It could be very important."

Once they'd returned to Khel's place, Martha took over the terminal. As the local Internet, it seemed like the best place to start looking for information, but where to begin? The one question she really wanted to answer was how to cure the Plague, but that was also the one question she was sure she wouldn't be able to answer on her own. What the Doctor had asked her to do, to figure out what was dodgy about the Plague Research Centre, wasn't the simplest of questions, either.

Martha asked the AI about the NTPCRC. It gave her some basic data: the location, which she already knew, the amount of people working there, the history of the Research Program from its earliest days, when they'd thought the Plague only affected petromites, through the frenetic period when they'd fought to contain the epidemic, to the current status quo. It was all very interesting, but not in the least dodgy.

She tried looking for information about the researchers, but the public profiles that the AI recited didn't tell her much. At best, she got some personal details, a resume and contact data, at worst, nothing at all. Some of the people with more data available were Darks, but the majority seemed to be Brights, including Gaer, the head of the program.

She inquired the AI about the publications of the Research Program so far, and the titles appeared in front of her, floating in the air in front of the hologram girl. Martha eyed them through. There were only a handful, and those were all about the Plague's effects on petromites and people. There was very little about the structure of the organism, let alone about any possible cures. Was that dodgy? Maybe not. They'd only been working on it for half a year. As far as Martha knew, that wasn't a terribly long time for something like this.

She sighed, and leaned back in the chair. She was looking for a needle in a haystack without the slightest idea of what the needle looked like, or whether it was in fact a needle at all. The Doctor had given her one sort-of specific clue, the word 'contrast'. She ran it by the AI, and found encyclopaedia and thesaurus entries describing the common noun, as well as a ridiculous amount of articles and conversations where the word had been used. Even if there was something suspicious among those, finding it would be well night impossible.

Disappointed in her progress, or lack of, so far, Martha decided to change tactics, and called Khif.

"I'm really sorry about the Doctor," Khif said. "He was such a lively and friendly person."

"And he's still going to be one once we've sorted this out," Martha stated almost angrily. "Which is something where you may be able to help."

"I don't see how. I'm only a guard. I barely know anything about the Plague."

"No, but I bet you've got access to more data than I do, all sorts of classified things and so on. There's something weird going on at the research centre where the Doctor is - it's almost as if they don't want him to get better."

"Some Darks can be like that," Khif said unhappily. "I'm truly sorry about it. I hope you understand that not all of us are like that."

"It's not that. There are lots of Brights working there, too, and they're no better. The Doctor would be able to cure this thing if only they let him work on it properly, but they won't. So, if there's anything you can do, anything at all..."

"Of course, I'll do what I can. Just don't expect too much. Martha Jones, I don't want to sound unkind, but - I know people who have lost friends or relatives to the Plague. I've seen what it's like. They were always hoping, always thinking that a cure might be found, until the very last moments. Sometimes they went on hoping even after they'd heard the news, thinking that there had been a mistake, an error in the data stream, that the person was actually still alive in Nest Town and just unable to reach the Network. I'm not sure if you truly appreciate how deadly the Crystal Plague is. There are no survivors."

"No Khiandrian survivors," Martha said, refusing to feel disheartened. "The Doctor's of an entirely different species - and he's brilliant. We're going to figure this out."

Khif looked at her, the sadness in her eyes making it clear that she found Martha overly optimistic. Nevertheless, she said, "We'll do our best, as always."


	11. Seven Hours

For the third time, the Doctor had to hide the sonic screwdriver in his pocket when a Khiandrian showed up. This time, it was the same young man the Doctor had met right after he'd escaped Nest Town, not the young woman who'd come to check on him the two previous times.

"What are you up to?" the Khiandrian asked.

"Oh, nothing, really," the Doctor replied casually. "Just killing time, you know." He took the sonic from his pocket, tossed it in the air, and caught it using his good hand. "Just an electronic toy. A puzzle sort of thing."

"Really? What does it do?"

"I'm not sure. Haven't solved the puzzle yet!"

He'd solved one puzzle, though, the Doctor thought, once the young man left. They were definitely keeping an eye, and an ear, and maybe even a nose on him, and not just in the medical sense of things. It felt likely that they'd overheard his words to Martha, and were overly suspicious because of that. It made his life much more difficult. He needed access to the local computers, and before he could get there, he'd need to hoodwink the surveillance somehow, but he wasn't getting anywhere at all. Every time he tried something, someone showed up. He wondered what they'd do if he just ignored them and kept working. Would they knock him out? He wouldn't put it past them.

He sat down on the bed for a moment, glancing at the data on the screen for a change. Nothing worrisome nor interesting there yet. All his readings were within normal range. The crystal growth was creeping down along his right side. It rather felt as if someone had slipped an ice cube under his shirt, except for the stinging pains triggered by even the slightest movement of the infected area. Was it growing downwards, and not up towards his head, because it was intelligent, and wanted to keep him alive as long as possible, or was it just taking the path of least resistance and following the pull of gravity?

He couldn't help marvelling at how fast the thing grew, and how efficiently it seemed to be using all available resources. He really wanted to know more about it, not just because his survival depended on that, but because it was incredibly clever. Nasty, but clever. He still didn't even know what it was. One single organism, or a big colony of single-celled creatures? Bacterial? Plant, animal, fungus? Something not comparable to any terrestrial organisms? How he wanted to see it under a microscope!

He had the nagging feeling that there was something familiar about this thing. That was a little odd, because he was absolutely certain he had never, ever seen anything like it before. Something as amazing as this he would remember, no matter how many lifetimes ago he'd last met it. He glanced at his right hand, still the only visible sign of the spreading infection. The only thing it reminded him of were khirindals, but that was just because both were crystalline in appearance. Similar appearance, different origin and structure.

He got up again, cautiously, doing his best to avoid unnecessary discomfort, and set to work on the computer again. This time, he'd see this through, he decided. Better find out once and for all how serious the locals were about keeping him off the case.

Within minutes, the same young man showed up again, a look of frustration on his face. "Whatever it is you're doing, just stop it, all right?"

The Doctor didn't move his hand or the sonic. "And what are you going to do if I don't?" he asked. "Give me the Plague?"

"Please," the man said, sounding exasperated. "I'm just doing my job here."

"Babysitting me is your job? Are you a guard?"

"Of course not," the Khiandrian said, sounding a little hurt. "I'm a research assistant."

The Doctor let the sonic fall and turned around. Maybe he should try an alternative course of action after all. "What's your name?"

"K'iem."

"And I'm the Doctor. So, research assistant K'iem... Can we speak freely?"

"Seeing as I'm the one who's supposed to be keeping watch over you..."

"Is this being recorded?" the Doctor asked, instinctively lowering his voice, even though he knew it would do no good.

"No, no," K'iem shook his head. "None of your data is. It's like..." He fell silent, an indecisive look on his face. "I really shouldn't be talking to you about this."

"It's all right. Go on," the Doctor said. "You can tell me. Whatever it is, I can help you."

"But if anyone finds out..."

"Well, they're not going to find out from me. I'm stuck here, and I'll be dead within a cycle or two, anyway."

"I guess you're right. It's..." K'iem lowered his voice to a conspiratorial whisper as well. "It's almost like they're just waiting for you to die, so they can conveniently brush away the crystal dust - so that there'll be no trace at all of you ever having been here," he blurted out.

"That's not very nice of them," the Doctor noted, not entirely surprised. "So, who's 'they'? Aren't you supposed to be on 'their' side?"

"I think most of the staff are in on it. I'm not. I don't know about sides. I don't know much about anything," K'iem said, speaking rapidly, as if he had been waiting for the chance to tell this to someone. "I'm just an assistant, and a boy, too. Gaer's an old-fashioned woman. You know how it is - she has me making tea and running errands, while the girl assistants get all the interesting tasks, and get to be in the know. She thinks I'm no smarter than a petromite nest. She'd never tell me anything important."

"You know what? I think you're very smart. You did the right thing when you decided to talk to me. Because," the Doctor took a dramatic pause. "I am going to cure this Plague, and you, K'iem, you are going to help me."

Since someone might notice if K'iem hung around the Doctor all the time, the Doctor began by sending the Khiandrian away, only asking to be left alone with the computer. Finally. The computer was a simple thing, just the flat screen in the wall and a voice-guided AI, but it was connected to all the other computers in the research centre. It only took him a couple of minutes to hack into the NTPCRP's intranet, a closed thing not connected to the planet-wide Network. He was a little disappointed in not being able to reach the Network at all, but that couldn't be helped.

The first thing he did was to look up a few pictures of the Plague organism. It was a colony of single-celled things, rather like a mould. The Crystal Plague as a fungal infection, now, that was a strange thought. The pictures were split into three categories, titled Phase I, Phase II and Phase III. He was easily able to match those to what he already knew about the Plague, and to figure out the entire life cycle of the thing.

Phase I, which was where he was at, was the autotrophic phase, where the organism's growth was mostly based on thermosynthesis. It used energy from body heat, carbon dioxide from the air, and trace amounts of things from the victim's skin to grow and spread. The outer crystal shell was inanimate, and the living, growing part below it clung to the skin with tiny, jagged barbs - which explained why it felt like it did.

At Phase II, the organism's metabolism changed completely. Once the crystal shell became a completely sealed cocoon, cutting off both the host's and the parasitoid's air supply, the Plague turned into a heterotrophic, decomposing organism, growing inwards, slowly converting the host's dead body to crystal similar to the outer shell.

Phase III was the crystal dust, the dormant in-between, which would activate as soon as it came to contact with living tissue. It was the toughest of the three forms, able to survive all sorts of extreme conditions, which was why the locals had no choice but to keep Nest Town under quarantine, indefinitely.

The Doctor had seen lots of strange things, but now that he really looked at this Plague organism, it struck him as really odd. Such a life cycle didn't exactly seem like the most obvious choice - more like the exact opposite. What was up with all the crystal building? It wasn't exactly energy-efficient. And what kind of an evolutionary process would create an organism that acted like this, doing a complete U-turn from a producer to a decomposer? Unless... Maybe it wasn't a natural evolutionary process at all.

He knew for a fact that thermosynthesis wasn't all that common in the universe. Khiandria was one of the few places where it was more common than photosynthesis. What were the chances that an organism alien to the planet, but relying on that very same process, would accidentally end up here?

The crystals looked similar to khirindals, but was that the only similarity? Petromites ate rock and turned it to crystalline structures. This parasitoid creature built crystals through a process that seemed entirely different, but then again, how many organisms in existence did anything even remotely like this?

Feeling like he was just on the verge of discovery, the Doctor attacked the research program's intranet with even greater zeal. If only he could find what he was looking for - it was very likely that it was in the database, since the Plague had struck petromites first - yes, there! The genetic code of a petromite. Compare that with the Plague organism, and - bingo! As different as they were, there were certain similarities that simply couldn't be coincidental.

Now that he looked at all the data from this new angle, he noticed many things, traces, signs, hardly obvious, but clearly there for the clever eye to see...

"How's it going?" K'iem's soft voice startled him out of his contemplation.

The Doctor turned around - and grunted, and had to lean against the wall, when his entire right side flared up with a sharp, icy pain, all the way from his shoulder to his toes. He slid to the floor, and yanked off his shoe and sock. The crystal growth covered most of his foot. He'd been so intent on his work that he'd been able to forget the way he felt. Now that he did think about it, he had to grit his teeth and take deep breaths to keep it at bay. This was too fast. Considering his earlier estimate, it should've taken over twelve hours before it got this far. The Plague was adapting as it went. At this rate, he'd be lucky to have twenty hours, let alone thirty-six.

"Doctor? Anything I can do for you?" K'iem asked sympathetically.

The Doctor looked up. "No, but thank you anyway. Well, there's one thing. A simple question. Why does everyone think the Plague came from another planet?"

"Obviously because..." K'iem frowned. "That's what they've been saying on the news all along. I think it's one of the first things the NTPCRP found out. Besides, there haven't been any serious infectious disease on Khiandria for ages. Where else could it have come from?"

"Where else, indeed," the Doctor said darkly, leaned back his head and closed his eyes, feeling shocked and disgusted, not to mention tired, and sick, and cold. That was one great discovery he'd rather not have made. Nasty, but clever, he had thought earlier. How right he had been. So very clever, but so terribly nasty.

"Actually, there's one other thing you could do for me, K'iem," he said. "My friend, Martha Jones. I need to talk to her. As soon as possible."


	12. Twelve Hours

There had to be something! It was getting late, and Martha was tired, but she wasn't going to stop until she found at least something that would help the Doctor somehow. After calling Khif, she had called T'ig. The old Khiandrian had been genuinely happy to hear from her, and devastated to hear about the Doctor. Apparently, there hadn't been anything about him on the news. Unfortunately, T'ig had had nothing to say on the subject of the Plague, nor contrast.

Martha was eyeing a list of news items and public conversations which had both the word Plague and the word contrast in them. They revealed absolutely nothing to her, and she was half asleep, when the AI suddenly announced there was an incoming call for Khel.

"Who's it from?" Martha asked, hoping that it might be the Doctor.

"Jess, daughter of Jem, calling from the Central Holding Facility," the AI replied.

A moment later, Khel appeared, accompanied by all three cavers. Martha stepped aside, and Khel sat down on the chair just as Jess's hologram emerged opposite her.

"How are things?" Jess asked. "Any news on the Doctor?"

"You haven't heard?" Martha said.

Jess glanced in her direction, obviously unable to actually see her. "No. I don't have a terminal of my own here, and the guards haven't told me a thing. What is it?"

"The Plague," Khel said simply.

"Oh. Oh, no," Jess said, wide-eyed. "Oh, dear. How?"

"The kidnappers took him to Nest Town," Khel replied.

"But it's going to be all right," Martha said quickly. "He'll cure it."

There was a short, rather uncomfortable silence. Martha could guess the others didn't quite share her optimism, but they were tactful enough not to say it aloud. Jess was obviously having a hard time trying to figure out how to take these news.

Brian changed the subject. "Are you all right?"

"I'm fine, darling. Just bored. I've got absolutely nothing to do until the trial continues tomorrow."

The trial! Martha had all but forgotten about that. Having to worry about it on top of everything else felt just plain unfair. "Can't it be postponed?" she asked.

"I doubt it. If he's got the Plague, I don't think the Fifteen will see any point in waiting, because they won't believe he can get better, no matter how long they wait. But I'll talk about it with Neir when I see her in the morning."

Jess only had twelve minutes for the call, and she spent a part of that alone with Brian. In the meantime, Martha tried asking Khel for help, but "contrast" didn't mean anything in particular to her, either.

Once Martha got back to work again, she decided to check the news coverage on them, just out of curiosity. To her amazement, she found only a vague mention of a "suspected kidnapping" at the Halls of Justice, and nothing more. There were lots of news about their unexpected arrival at the City of Lights, as well as the bombing of the surface train, and complete 3D recordings of the trial, but not a single word about the Doctor becoming the latest victim of the Plague. That had to count as dodgy. More than that, it screamed "conspiracy" at Martha.

Aside from that one discovery, Martha found nothing new, no matter how hard she looked. Khel finally persuaded Martha that she'd be more successful if she wasn't about to fall asleep all the time. Reluctantly, she joined the rest of the humans, who were already sleeping on mattresses in the living room.

She was woken up by Khel's son, who told her anxiously that she had a call, from a stranger! It wasn't quite the Doctor this time, either, but the young research assistant did have a message to her from him. The Doctor wanted to see her as soon as possible.

Martha found Khel in her study, working on a 3D model of a cave apartment. Without waking the other humans, they headed towards the NTPCRC as quickly as they could. There, they were greeted by the same research assistant who had called Martha. He would allow only Martha to see the Doctor, so Khel had to stay behind and wait with him.

It must've been about eight hours since Martha had last seen the Doctor, and during that time, things had clearly changed for the worse. He did look sick now, his skin almost the same colour as the crystal covering his right hand and foot. He was sitting by the force field, with his back against a wall, hugging his left knee close to his chest with his left arm, as if for warmth. Martha glanced at the computer screen in the wall, but the readings were displayed in an alien manner and in alien units, and didn't tell her much.

"How are you feeling?" she asked him.

"Oh, you know, a little plagued," he quipped. She noticed he was breathing shallowly, like someone who had broken ribs and was trying to avoid jarring them. "And cold," he added.

She was a little surprised to see that the coldness affected him this much. After all, she'd seen him survive minus two hundred degrees. Whatever the Plague did, it couldn't possibly cause anything even close to such an extreme temperature. "Isn't there anything you can do about that? Or any way I could help you? Emergency blankets or something?" she asked.

"Not really," he answered, his expression somewhere between a smile and a grimace. "It's a bit of a balancing act. Any attempts to compensate for the heat loss will only give the organism more energy and cause it to grow faster. On the other hand, if I just allowed my temperature to drop, to stop it from spreading, I'd start getting hypothermia symptoms."

"Couldn't you do that hibernation thing again?"

"It'd just be putting off the inevitable. Besides, I need to be conscious. There's work to do. I found out something." He got up, his face screwed up in pain as he moved, and turned to face the force field, fixing Martha's eyes with an intense look.

"Just how far has it spread?" Martha asked softly.

"That's really not important right now."

"Doctor, I need to know - it's spreading faster than you expected, isn't it? How long have you got?"

The Doctor sighed, opened the few top buttons of his shirt, and pulled the fabric aside, to reveal that the crystal covered half his chest now. "Don't know how long. Maybe ten hours, give or take a few."

"So, what you've found out - is it a cure?" she asked hopefully.

"No. I'm still working on that. It's..." He pulled a face. "I hate this. I really do, and I've got no absolutely concrete evidence, but, well, it very much seems that this Plague is neither alien to this world, nor natural."

"You mean... Someone made this thing?" Martha said, disbelieving and horrified. "Like a biological weapon, or something?"

"Yes. And most likely it was someone Khiandrian, because it's similar to Khiandrian life forms."

"Why do they say it's alien, then? And how come no one else has noticed this?"

"Because this place is more of a sham, a cover, than a real research centre. Who knows, some of the people here might have helped create this thing. That's why they didn't want me poking around. It's probably why I got attacked in the first place, too. I'd been asking around about the Plague, and they were worried I'd find out the truth."

"And it explains how the kidnappers were able to get you to Nest Town through the quarantine safeguards. It really does fit," Martha said, and frowned. "Hold on a second. Should we even be talking about this here?"

"We can talk. K'iem, the friendly young fellow who's guarding me, is on our side."

"All right. So. Um, did you know that the news about this entire incident, you and the Plague, it's been completely swept under the rug? Not one word of it in the Network. I doubt we'd have found out you're here if Khif hadn't told us!"

"Well, I didn't know that, but it doesn't surprise me in the least."

"It's a conspiracy," Martha stated. "A secret extremist group."

"Yup, a pretty classical secret society, by the looks of it - well hidden, with plenty of friends in high places."

"But why?" Martha asked, still having trouble grasping the idea that this terrible epidemic was something that had been caused deliberately.

"That, I still can't understand," the Doctor admitted. "But, I bet if we find out who did it, it'll be easier to figure out the motives. Darks hoping to cause an anti-alien panic? Brights wanting to make some point about petromites? Mad scientists planning on taking over the world? I'm absolutely certain that Gaer, the head of this place, is in on it, so that might be one place to start from. Did you find out anything about 'contrast'?"

Martha shook her head. "Nothing at all, and I really tried."

"Hm. I may have misheard it... I was just thinking it might well be the name of our Plague-creating secret society."

"Even if it is, does it really matter? I mean, this is all horrible, and no doubt it's very important, but what we really need to figure out is how to cure this thing. You won't be able to help anyone if we don't - you'll be dead in less than a day!"

"I can figure it out, no sweat," the Doctor promised. "Quite literally, too, since this blasted bug is eating it. Well, anyway. You have your job, I have mine, and you need to go before someone other than K'iem realises you're here." He took a step backwards, grimaced, and very nearly fell when he tried to put weight on his bad foot.

"But I could help you!"

"Martha, you'll be helping everyone on this planet if you can figure out who's behind this atrocity. That might help me, too. I can't believe anyone would be stupid enough to let loose something like this without the means to stop it."

"Okay," Martha said. The Doctor was right, of course. "But I'll be back soon."

**************

"My shift ends in half a tenth, and I know for sure that the girl who's taking over from me won't choose to be friends with you," K'iem told the Doctor soon after Martha had left.

"That calls for some special arrangements, then."

Together, the Doctor and K'iem were able to rig all the monitoring equipment in the room, from cameras and microphones to medical scanners, to show that the Doctor was resting on the bed all the time.

"Is this amazing or what? She's not going to notice anything suspicious," K'iem said, delighted. "Usually, people really don't move around at all when the infection has spread this far. Hurts too much, I've heard."

"Yeah, it does," the Doctor admitted, and gritting his teeth, shuffled over to the computer.

He should have all the data he needed, now. All he needed to do was to figure out how to stop this thing. He skimmed the database to learn if the locals had actually done any proper research on curing the Plague. If this whole place was just a cover, the chances were there would be nothing at all, or that all the data would be fabricated.

What he found took him by surprise. They had been doing research, and it seemed entirely genuine. They had tried all sorts of things against the organism, from direct force to changes in environmental conditions - different forms of radiation, different lighting, different temperatures, sonic vibrations in different wavelengths - and found out that the organism was so tough that in all cases, the host would've been long dead before there was any effect on the Plague. Cutting the Phase I organism's air supply wouldn't help either. It would only leap to Phase II prematurely, and start feeding on living tissue. Ew.

After a while, he ran into files with extra safeguards. It actually took him some time to get past those. When he saw what was in them, he understood why.

It was the cure - only it wasn't a working one. It was, apparently, what the creators of the Plague had originally intended as the cure. A cure to a disease that was only harmful to petromites, according to the notes, which were dated half a year ago.

It seemed they had never meant to kill any people, only petromites. They hadn't let the Plague loose without a cure, either, but it had mutated in ways they hadn't expected, and now, they really had no cure. No way of stopping it. They could only keep it contained, and make sure that no one found out where it had come from. They were so intent on keeping that secret that they wouldn't even let him help.

The original cure was a pesticide, or rather, mouldicide sort of thing, a complicated chemical compound that would kill the Plague organism without harming the host, a synthetic counter-attack almost as clever as the Plague itself. As clever as it was, it would not be able to reverse any damage that the Plague had already done. If the organism had moved to Phase II, there would be no converting the crystallised tissue back to flesh and blood. That was simply not possible. Not that it mattered - at that stage, the host would be dead, and it would be too late, anyway.

Now, then. He stood up straight, and would've clapped his hands if that hadn't been both difficult and painful. At least this gave him something to start from. He could simply modify this old cure so it that would work against the current strain of the Plague. Of course, that was much easier said than done.

* * *

**Author's Note: **I'm a wee bit worried about the fact that the previous two chapters have only received three reviews altogether - I hope it's just because you're all busy enjoying the summer (which I totally understand :) , and not because I've taken a wrong turn with the story somewhere and everyone's lost interest...


	13. Eighteen Hours

**Author's Note: **Thank you for letting me know you're still reading and enjoying the story! :) And worry not - I would finish this even if it had no reviews at all.

This chapter is a little shorter than the rest, and the following one will be, as well, since they were originally one very long chapter, which I decided to split in half.

* * *

**13. Eighteen Hours**

Martha had been planning on taking up the search at Khel's terminal again, but when she met Khel outside the Plague research centre, she found out that it would have to wait. "The trial begins in half a tenth," the Khiandrian informed her. "We've got just enough time to pick up the others and get to the Halls of Justice." Jess hadn't been able to postpone the trial, which meant that Martha would have to waste her time listening to hours of alien legal talk, while the Doctor kept getting worse.

The trial turned out even more tedious than Martha could've expected. The Fifteen began from the very beginning, which meant that the entire session was spent discussing the first time Jess had broken the Quarantine Law, when she had left the planet twenty years ago. It went on for hours and hours, with quarantine specialists and travel officers and even Jess's parents giving statements. The latter refused to even look at their daughter, who stood on the central platform all through the session, as defiant and unapologetic as she'd been during the first session, answering questions in a firm, unwavering voice. Neir stood by the platform, and, as far as Martha could understand, did her best to act like she was trying to make Jess seem innocent, while actually subtly making her appear more guilty.

Martha could do nothing but sit on the stone bench, just behind the Fifteen's row, feeling too anxious for words. She considered trying to sneak out. She was free, after all, and there were no guards keeping an eye on her. Then again, she wasn't sure how the Khiandrians would react to that, and whether it would affect the trial somehow. She didn't want to cause Jess any more trouble than what the Khiandrian already faced. Besides, where would she go? She didn't think she'd be able to find her way back to Khel's place on her own, let alone to the NTPCRC - and going back there without even trying to figure out the conspiracy would be exactly what the Doctor didn't want her to do. So, she sat, and waited, and worried.

Once the session was finally over, Martha and the other humans were given a moment together with Jess. Neir was there as well, and on a whim, not expecting to get an answer, Martha asked the spokesperson if she knew anything about contrast.

There was the slightest flash of something on the Neir's face, a hint of a frown, a trace of surprise or alarm. She hid it quickly. "Contrast? It has to do with colours and hues, or opposites, right?" she said, feigning ignorance, but Martha was certain she hadn't just imagined that initial reaction. The fact that Neir made a hasty exit soon after that was more than a little dubious, too.

Later, once they'd bid farewell to Jess and were in a tram, on their way back to Khel's apartment, Martha finally had the chance to ask Khel about the spokesperson. "Do you know Neir well?" she began.

"Not personally, no," Khel answered. "She's more of a work contact and a friend of a friend. I was rather surprised when she called me and offered to take this case. She's a prominent spokesperson - most people on the planet have heard of her. She's of a very old noble family, too. Royal blood, actually, not that it means anything these days."

Royal blood. That reminded Martha of something. Hadn't Khel said earlier that the Deep, the group who had taken the Doctor to Nest Town, were royalists? Could there be a connection? But Martha had thought that... "Neir's a Bright, isn't she?"

"Yes. Quite an influential one, too."

"Oh. Do you know if she happens to know Gaer? The head of the Plague research program?"

"Gaer is a notable Bright too, and they're both active in local politics here in Maze City, so yes, I suppose they know each other. Why are you so interested in Neir?" Khel asked.

"No reason, just wondering," Martha said vaguely. She wasn't going to explain this to Khel, when she no longer had any idea who she could trust.

It might well be just random coincidence that the two women were connected. Maybe they didn't really know each other. Maybe they had nothing to do with the Deep. Martha might be building conspiracy theories based on nothing. Then again, Neir had been there when the Doctor had been kidnapped, and her having volunteered to take the job made her appear even more suspicious. She definitely had been in the right position to make that operation possible - but the kidnappers had been Darks!

Neir and Gaer were Brights. The kidnappers were Darks. Neir had royal blood. The kidnappers were royalists. There were both Darks and Brights at the research centre. Brights and Darks working together in a sinister secret society. Bright versus Dark - so, Contrast?

Could it really be? Would they really pick a name as transparent as that? Then again, it wasn't as if they were shouting that name aloud all around the planet. It was well hidden. Neir must've been really surprised to let her guard slip like that when she'd heard Martha mention the name. Besides, the other extremist organisations didn't exactly have imaginative names, either. The Deep and Obsidian were pretty obvious picks for Darks. Come to think of it, Khiandrian place names followed the same pattern. Nest Town, Maze City, the Halls of Justice... They were all very descriptive and straightforward.

It felt too fitting not to be true. Still, even if it were true, Martha couldn't imagine why these people would've wanted to punish their own planet with something as terrible as the Plague. How exactly had it helped to advance the royalist agenda?

She was still pondering what to do next when they reached their stop. Should she try and find more evidence for her theory, or just go straight to the Doctor and explain it all to him? Should she tell the other humans? What about Khel? Jess's sister didn't seem to be a part of this conspiracy, but could Martha be sure about that?

They stepped out of the tram, climbed up the two sets of stairs leading to the residential level where Khel's apartment was - and found themselves surrounded by a circle of grim-looking Khiandrians in black uniforms. Before Martha had time to ask what was going on, one of the guards grabbed her firmly by the arm, and pulled her aside.

"What -" Martha began.

The guard shushed her. "Keep walking, and don't draw attention to us. It's all right. I'm a friend."

Now that she looked at the guard, Martha recognised her as the very same woman she'd helped after the train crash. Behind them, Martha saw her friends confront the other guards. Khel was shouting at them angrily as they surrounded her and the humans, who seemed too confused to act at all.

Martha's guard guided her to the nearest staircase leading up. As soon as they were away from sight of the others, the guard took up running, pulling Martha along so insistently that she had little choice but to follow.

**********

Five hours after he'd found the original, useless cure, the Doctor was still exactly where he had started from. He'd had the AI run simulations with modified versions of the cure, but none of those had had any effect on the Plague organism. The only thing that had advanced at all during the time that had passed was the infection.

He had allowed his temperature to drop as he worked, consciously keeping himself from shivering or otherwise producing more heat, hoping that it would slow the spread of the crystal growth and buy him some time. The only result had been that he now felt very cold indeed, and his thoughts were sluggish due to his slowed-down metabolism.

For the first time since he'd been infected, it occurred to him that he might not be able to come up with a cure in time. Maybe this pessimism was only another symptom of hypothermia, but still... Sure, he was more clever than Khiandrians, but they weren't exactly stupid either, having been able to create this Plague in the first place. If they hadn't managed to find a working cure in half a year, could he really be able do it in a few hours? And even if he could, he was only working on simulations here, on theoretical models. He was sure the Khiandrian researchers could easily synthesise the compound, but it wasn't as if they were going to do that for him just because he asked nicely.

He had the computer display his own data for a change, and found that it was full of warnings, blanks, and things labelled as estimations. Apparently, the crystal shell prevented the scanners from getting proper readings. It now covered everything except for his left arm and shoulder and his head. There was no longer any point in trying to avoid discomfort. The only comfortable position would've been lying down, not moving at all, not even breathing. The crystal enveloping his chest barely gave way enough to allow shallow breaths, each single one of them painful. He could imagine that by this time, most victims would succumb to the inevitable, simply give in, fall unconscious, and suffocate.

He had no intention of giving up, but he did need a break. He slid to the floor, and relinquished the mental hold he'd had on his thermoregulation. Instantly, shivers wracked his body. He let his teeth chatter, and took as deep breaths as he could, doing his best to gather his wits, to get rid of the cold-induced stupor.

He wondered what would happen if he failed. He'd be able to hold on for some time once the crystal growth had covered him entirely. He wasn't sure if that was a good thing. The thought that he might be conscious when the Plague moved on to Phase II was terrifying.

Whichever the case, eventually, it would all be too much, and he would regenerate, and then what? Would the Plague organism be able to soak up all that energy? Or would it be destroyed, or would it simply shift to the dormant phase, only to infect his new body right away, again and again, until he had none left? He really had no idea.

He hoped Martha would show up soon. It always helped if he could bounce his ideas off someone, especially someone brilliant - not to mention that he'd rather not be all alone if the worst came to pass. She'd promised to return, and he would've expected her back by now. He was sure she would've come, had she been able to. He really hoped she was all right, and not in any trouble.


	14. Twenty Hours

Martha tried to ask the guard again and again what was going on, but she got no answer. They ran through tunnels, taking random, sudden turns, calling to mind Martha's earlier escape attempt with the Doctor, in the City of Lights. At times, when they reached busier streets, they'd slow down to avoid drawing attention. They seemed to be headed out of the city centre - there were less and less people around them, and less doors in the walls. They'd been going up and down so many stairs that Martha had no idea how far they were from the First Level.

Eventually, they reached a tunnel almost as verdant as the one they'd seen after the train crash. There, the guard opened a door half hidden behind tall, hanging plants, and ushered Martha inside.

It was a small apartment. Martha could see three rooms from where she stood, and that seemed to be all there was. The place looked abandoned, all the furniture and the decorative cloths and carpets covered in dust.

"The grandfather of a friend of mine used to live here, but he moved away when the Plague struck. This neighbourhood is right next to the quarantine barriers. No one lives here anymore. We should be safe for at least a few tenths," the guard explained, still sounding anxious.

"Safe from what?" Martha asked. "What's going on?"

"Sorry. I really do owe you an explanation. My name's Meg," the guard said. "You remember me, right?"

"I do. I'm Martha."

"Pleased to meet you, Martha, and thank you, once more," Meg said. She placed her hands on Martha's shoulders, in the Khiandrian equivalent of a handshake. Martha returned the gesture.

"So, I've been in Maze City on sick leave since the train crash," Meg went on. "Around half a tenth ago, Khif called me, and asked if I could help you. You see, they've issued a warrant to arrest you and your friends, suspected of illegal activities, most importantly co-operation with the Sentients."

"Who? I've never even heard of them!"

"They're one of the more violent Bright extremist groups, very pro-alien. An obvious scapegoat to pick. I know you have nothing to do with them, and so does Khif. That's why we're here."

"But I still don't understand..." Martha began, and fell silent, biting her lip, as realisation dawned. "Contrast! I asked Neir about it. She must've decided that I'm a threat - but that can't have been much more than an hour ago - right, half a tenth, just like you said! They're fast. Do you know about it, then? Contrast, I mean? The conspiracy?"

It was Meg's turn to be at a loss. "What's Contrast? I just know that someone's trying to frame you, someone with lots of contacts. I don't know why."

"I'll explain - I'll need to explain it to Khif, too. Can we call her from here?"

"Sure, the terminal should work, even though it's a bit old."

"Can they trace us or something? Listen in on us?"

"They'll locate us eventually, but it's going to take some time, when they've got no idea where we are. It shouldn't be a problem yet."

The terminal's age only showed in the quality of the hologram: unlike the very life-like images Martha had seen earlier, this one was hazy and blurry and transparent. Meg complained that the sound was horrible, too, but Martha couldn't even tell the difference. They asked the handsome AI to contact Khif, and to Martha's relief, she answered right away.

"I've been expecting your call," Khif said, in the manner of a greeting. "Now, I know there's something very odd going on. I looked into things, like you asked, and found several strange, covert operations related to the Plague, as well as unexplained, classified files - and now there's this warrant, which just came out of nowhere, all of a sudden. What's happened? What have you found out?"

Martha took a deep breath, and started from the beginning, speaking so fast that she wondered if they'd catch half of it. She told them about the Doctor's discovery, that the Plague was a deliberately manufactured thing, and then, her own theory about Contrast.

Khif listened intently, her face grave, nodding now and then. "Contrast," she repeated, as if testing the word. "So, that's the name of these scum. Everything you've said matches my findings all too well."

"But it can't be true!" Meg cried out, looking from Martha to Khif's hologram like they'd both lost their minds. "Why? Why would anyone do anything like this?"

"I've been asking the same question," Martha said.

"They're royalists," Khif said thoughtfully. "What's changed since the Plague struck?"

"More violence and extremist attacks?" Martha suggested.

"The Emergency Laws. Practically no aliens on the planet. Tighter control in everything. More power to the government and the guards," Meg listed.

"Exactly. They want the old times back, and with the paranoid atmosphere, that's where we're headed," Khif said. "I wonder if they're planning on an actual coup, or if they hope to get there through less direct means..."

"We've had it backwards all along," Martha muttered. "We thought the Plague was a natural disaster which was turned into a political thing, but it's the other way around. Politics came first."

"What are we going to do?" Meg asked, her voice flat. "What can we do? There's only three of us, against who knows how many Contrast conspirators! How do we even know who we can trust? What if the whole government is in on this?"

"They're not," Khif said soothingly. "The Chairperson and a majority of the ministers are Dusks. I'm sure they don't know anything about this. If Contrast already had the government in their pocket, they wouldn't have needed the Plague."

Martha really had no idea what to do about the conspiracy, but she was sure the Doctor would think of something - and every second she wasted sitting here might be his last. She stood up. "Before we do anything else, I've got to get to the Plague research centre. The Doctor may not have much time left. Are we far from there?"

"We're right below them, actually. Go four floors up and you're almost in their backyard," Meg answered. "But you can't go there. They'll capture you - they may harm you, even kill you!"

Looking at the two guards, Martha knew exactly what she was going to do. Not just how she could get to the research centre safely, but also how she could make sure that if Contrast had any way of curing the Plague, they'd use it to save the Doctor.

"They won't," she said. "Not when I've got you as insurance."

**********

Instead of Martha, the Doctor's current guard showed up, a girl as young as K'iem, with a haircut exactly like Gaer's. "I thought you'd be lying in bed," she said, sounding only mildly surprised and suspicious.

"I was. I tried to get up and found I couldn't," he told her. He didn't need to act to make his voice suitably miserable. He simply allowed himself to sound as bad as he felt.

The girl took pity on him. She entered the room through the airlock door, wearing a smart fabric suit, and helped him to the bed. She lingered for a while, but luckily, didn't look too closely at the computer. Finally, she left, and the Doctor could get back to work.

And he worked, and he worked, concentrating hard on his task to keep his mind from the fact that he barely had enough strength left to stand, leaning on the wall with a hand on both sides of the computer screen - both hands now crystal-coated - guiding the AI to try countless improvements to the original cure, until he simply couldn't stay upright any longer.

He slumped to the floor, and relied on the AI to describe everything to him. Even speaking felt painful, as the cold, barbed fingers of the Plague crept up along his throat. It was like drowning in some sub-zero liquid.

He almost didn't understand the words when the AI announced, "Result of this simulation: one hundred percent elimination of the target organism."

Finding new strength in his unexpected success, he struggled to his feet. It was incredibly difficult, when he was barely able to bend his knees at all, but he really needed to see this. He reran the simulation, and witnessed with his own eyes how the compound he'd designed practically wiped out the Plague organism.

He'd done it - but he didn't feel the least bit victorious. He was running out of time, and he still had no idea how he'd be able to get this very complicated and so far purely theoretical cure actually manufactured.

"It's magnificent," a voice said behind him. He hadn't noticed anyone enter the room. He half turned, half fell to sit on the floor, facing the force field, and saw Gaer standing behind it.

"You really were telling the truth when you said you know a lot about these things. Seems I made the right call when I decided to let you mess around with our files - you see, the system alerted me the instant you accessed the classified documents. Thank you very much, Doctor. I'm going to start the empirical testing right away. If this cure really works, you've solved a major problem, and saved many lives. I'm afraid yours isn't among them, though. May your spirit's path to the afterlife be easy," Gaer said, without a hint of emotion in her voice or on her face. Just like that, she turned around and walked away.

The Doctor tried to shout after her, but the crystal now covered his mouth, his lips literally sealed. He struggled to get up from the floor, but he was simply too exhausted and too cold to force his stiff, numb limbs to move. Nothing he could do, then.

So, was this it? The idea was so surreal that he didn't even feel like panicking. This couldn't possibly be how it was all going to end. Something would happen, something would change, Gaer would change her mind, K'iem would show up, Martha would return...

As the crystal crept over his nostrils, he tried to find solace in the thought that even though he had failed to save himself, at least no one else would have to die of this thing. He had no idea how long he could last without air in his current state - or how long it would take for the Plague to move on to Phase II and start gnawing at his skin. He really hoped he wouldn't be conscious enough to actually feel that.

He closed his eyes, and ever so slowly, the solid, icy tide rose to cover his ears and his eyelids, leaving him blind, and deaf, except for the echo of his hearts hammering against his crystal-covered rib cage.


	15. Twenty One Hours

Martha was expecting to run into an army of guards at the NTPCRC, but instead, she didn't see a single soul. The place could've been abandoned. What was going on? Moving warily, feeling it couldn't possibly be this easy, she entered the building where the Doctor had been earlier.

A young Khiandrian was waiting for her right behind the door. Martha recognised him as K'iem, the research assistant who was supposed to be on their side, one of the good guys. "I'm glad you came!" he said in a low, hurried voice. "The Doctor was able to create a cure, but Gaer isn't going to give it to him, and I -"

"There's a cure? That's great!" Martha said hopefully. "How is he?"

"He's... It's probably too late already," K'iem said, instantly crushing her hopes. But she could still understand what he was saying, so it couldn't be too late, could it?

"The thing is," K'iem went on, "Gaer is expecting you. She sent me here to wait for you, and I'm supposed to inform her as soon as you've arrived. She has a team of guards at the ready as well, but she thought it best to try and deal with you as quietly as possible."

"Does she know you've double-crossed her?"

"I doubt it. She probably doesn't think I'm smart enough to do anything like this - and maybe she's right, because I'm not sure what to do. The Doctor's most likely beyond help. I should just tell you to run. You're not safe here. If Gaer catches you, she'll..."

"I came here to rescue the Doctor, and that's what I'm going to do," Martha said, determined. She was terrified, of course, but his life depended on her. Backing up now was not an option. "I'd like to meet Gaer, too. You go fetch her. I'm not going to run away."

K'iem left, and Martha walked over to the Doctor's room. When she saw him, she felt like she'd been frozen and crystallised herself. It was as if someone had carved a crystal statue of him, and dressed that in his clothes. Every bit of skin she could see was covered by the white, translucent growth. He was sitting on the ground, his back against the wall. The expression on his face was serene, his eyes closed, as if this sculpture depicted him taking a rare break from all that running and problem-solving. The computer screen above him didn't show his readings. Instead, there was a complicated 3D-model of a chemical compound, probably the cure. That meant she had no way of knowing whether he was still alive within that crystal shell.

She heard someone enter the room, and turned to face them. It was a woman, taller than Martha, which made her very tall by Khiandrian standards. She was wearing the dress-like gown with lots of pockets which seemed to be the standard attire of the researchers. The haughty look on her pale face and in her cold, colourless eyes instantly reminded Martha of Neir.

"You must be Martha Jones," she said.

"And you're Gaer," Martha replied.

The woman inclined her head ever so slightly. "Your friend was a truly extraordinary man," Gaer said, actually sounding a little awed. "But just like you, he knew too much. You do understand that what you see there, the state he is in, that's your fate as well?" She had raised her hand, and Martha saw she was holding a stun gun.

"I know a lot, yeah," Martha said quickly, hoping she sounded braver than she felt. "I know about Contrast, and I know you're behind this Plague. There's one thing where you're wrong, though. That's not my fate, and not his, either. Because I'm not the only one who knows about all this."

"We already have your alien friends in custody."

"I'm not talking about them. I have other friends - Khiandrian friends. They know about this, too, and they're telling their friends right now. If anything happens to me or the Doctor, they will tell everything to everyone. You might be able to catch some of them, but you'll never get them all. You better put that gun down."

Gaer lowered the gun slowly, staring at Martha. Her expression was still perfectly controlled, but as she spoke, her voice shook with anger. "You're lying. Who would be friends with alien criminals? Who would believe the stories of the likes of you?"

"You'd be surprised," Martha said defiantly. "I already know the Doctor discovered a cure. Now, you're going to give it to him, or the whole planet will know about Contrast within the cycle."

"How can I be sure that you won't just tell everyone about us anyway?"

"You can't, but at least it won't happen quite as quickly as it will if you don't help him."

"We haven't even had the time to test the cure properly! For all we know, it might not work."

"It'll work. If he said that it works, then it will."

At Martha's last sentence, Gaer's brow furrowed in a confused frown. The Khiandrian replied, her voice still seething - but the language sounded completely alien to Martha.

"He's running out of time!" she shouted at Gaer, knowing full well that the Khiandrian wouldn't understand her anymore. "Do it, now! Come on!"

Gaer sighed, nodded, said a few words in a tone that Martha interpreted as surrendering, and headed out of the room.

Before going after her, Martha turned towards the force field once more. "Doctor..." she whispered. "Hold on. Please. Just a little longer."

She caught up with the researcher near the entrance. Gaer was gazing after K'iem, who was hurrying out of the building. She tried to explain something to Martha, her voice matter-of-fact now.

It seemed Martha's plan was working, but could it really have gone this smoothly? She couldn't be entirely sure that it had worked until something actually happened. Besides, there were a dozen tricks Gaer might still try to pull. Being unable to communicate with the Khiandrians properly made things even worse, and left Martha feeling strangely helpless.

Gaer took Martha to another part of the small building, into a dressing room. There, she handed her a protective suit, just like the ones they had worn on the surface, and similarly wrapped. Gaer indicated the packaging with her hands and said a few almost friendly words, probably attempting to assure Martha that it was perfectly safe.

Martha accepted the suit and dressed in it, wondering if she was being stupid and making a huge mistake. This was really risky, after all. Even if the suit was intact, Gaer might try and damage it once they were inside the Doctor's room, or stun her and undress her. Still, it wasn't as if she had much choice.

Soon after Martha and Gaer had both got dressed in the suits, K'iem dashed to the room, and handed Gaer a transparent bottle with a spray nozzle. As Martha's eyes met his, he gave her a conspiratorial wink. Martha had no idea what that might mean, but it made her feel a little better.

The two women entered the isolation room through the airlock door. Without further words, Gaer walked over to the Doctor's statuesque form, and sprayed him all over with whatever was in the bottle. Right there, Martha saw another flaw in her plan. How could she know whether that really was the cure? It would be awfully easy for Gaer to claim that she had tried to give it to him, but that it simply hadn't worked.

The Khiandrian stepped back and said a few words, not to Martha, but to the computer. The screen switched to display the Doctor's data. Martha's heart sank at the sight of it. There was nothing there. As alien as the display was, there was no mistaking the flashing warnings and the absence of any readings. No breathing, no heartbeats, no brain activity.

Martha knelt by the Doctor's side. There was no change in the crystal cocoon. How long would it take for something to happen, if that had actually been the cure? It would have to be fast, or it would've been all for nothing. It might be too late already.

Gaer placed a soothing hand on Martha's shoulder. With a sympathetic look on her face, the Khiandrian spoke a few soft words, and gestured towards the door. The message was clear: "I'm sorry. It didn't work. We should go."

"Come on, Doctor," Martha whispered, and raised her gloved hand to touch the Doctor's crystal-covered cheek.

When she withdrew her hand, a small crack had appeared in the crystal, right where her fingers had been. It began to widen and spread, and as she watched, other cracks appeared in every part of it that she could see, on his bare feet, his hands, his neck and his chest. They formed a criss-crossing web, and the sections of the crystal growth which were surrounded by cracks started to darken and curl at the edges, like burning paper. She brushed at the crystal covering his face, and it fell off in big flakes, revealing skin that looked red, as if with sunburn.

Gaer muttered something that sounded very much a curse. To her amazement, Martha heard someone chuckle in reply. It was K'iem, who was standing at the other side of the force field, staring at the scene, a very smug look on his face. He began to speak, his tone matching his expression, lively and victorious.

Listening to his unintelligible chirping with half an ear, Martha eased the Doctor to lie on the floor. She sought for a pulse at his neck. The protective fabric covering her fingers was so thin that she could actually feel how cold his skin was. Aside from that, she felt nothing. Nothing at all.

But the cure had worked, hadn't it? It couldn't possibly be too late. No. Martha refused to believe that. She'd witnessed him bounce back from seeming lifelessness before, with a little help. He could do it again. He had to. She tilted his head back to secure his airway, getting ready to start CPR, when what K'iem was saying caught her full attention.

"Yes, I know you asked me to fill the bottle with thorngrass venom. I just chose not to. I'm actually not stupid, and I've had enough. I know you're going to fire me. That's why I've already sent my resignation directly to the Minister of Health, with copies to the High Commander of the Guard, and the Chairperson's office, complete with a few select files and notes."

"You will..." Gaer began, her voice nearing a growl.

"Uh-uh, I will be going now," K'iem said, grinning cheekily. "I guess you won't understand what I'm saying, but thanks, Martha, Doctor. Bye." He turned on his heel, and fled. Gaer rushed out of the room to go after him, leaving Martha alone with the Doctor.

Martha had understood every word of what they had said, and that could only mean one thing.

She turned to look at the Doctor again. Barely daring to hope, holding her breath, she pressed her ear against his chest - and cried out in delighted disbelief when she heard two heartbeats, faint and slow, but definitely there. She glanced at the computer screen. It was filling with data now, although some of the warnings still remained.

The Doctor's eyelids were fluttering. He sucked in a breath through his teeth, and released it in a pained sigh. Then, still breathing heavily, he opened his eyes. Martha quickly reached to wipe the remains of the Plague crystals from around them.

He blinked at her blearily. "Martha," he murmured, his voice raspy.

"Hi, there," Martha said, all smiles. She crouched closer again and, as awkward as it was when he was lying on the ground and she was dressed in a protective suit, grabbed him in a crushing hug.


	16. NTPCRC

Air.

Wonderful thing, air. He really had missed it, even while unconscious.

Enjoying the much needed flow of oxygen to his system, the Doctor blinked to clear his eyes and to bring the figure hovering above him into focus. It wasn't difficult to guess who it was. Something else he had sorely missed. Someone, to be exact.

"Martha," he said.

"Hi, there," she said, and hugged him tightly enough to squish out some of that precious air. He was too dazed to actually return the gesture, but he somehow managed to manoeuvre his hand onto her back and pat it weakly. It felt weird. His hand, that was, not her back. The same as the rest of his body, not exactly painful anymore, and not cold, either. More like the opposite, and quite itchy. Her hug was making that worse. He cleared his throat, and Martha let go of him.

"It worked, then?" he asked her. Speaking felt like a challenge, and his voice came through all croaky.

"It did," she replied, combing his hair with her fingers to clear off the sticky stuff clinging to his scalp. She stopped to rest her hand on his forehead. It felt cool against his skin. "How are you feeling?" she asked.

"Much better, thank you," he answered, tried to sit up, and had to fall back, gasping, when the itchiness turned to a nasty burning sensation.

Martha placed a gentle but firm hand on his chest to keep him down. "You should lie still for a bit, okay? We're not in a hurry."

"We're not? How did you..."

"I threatened to let the whole planet know about the conspiracy. About Contrast - they're a secret royalist organisation made up of both Darks and Brights. So, Gaer promised to give you the cure - except that she tried to trick me and use a false one, but then K'iem gave you the right one anyway. They both left just a few minutes ago, so I think it'll take a while until Gaer or her friends show up."

"Right," the Doctor said, straining to process all that information. Lying down a little longer did sound like a very good idea. Just a minute or two, so that he could pull himself together.

Instead of trying to get up again, he concentrated on what was going on in his body. Everything felt mostly all right - he was tired and dehydrated, but that was to be expected. There was one strange thing, though. He raised his hand in front of his face. There were fragments of the Plague growth still sticking to it. The crystal was no longer translucent and white, but a dull, matte grey. His skin didn't look its normal pale shade, either, but an angry, inflamed red, which matched the way it felt.

"What's up with that?" Martha asked. "And how did you even survive? For a while there, I thought... The scanners picked up no life signs at all, but you just - woke up. How's that possible?"

The Doctor coughed a little to try and clear his throat again. He felt as if he had swallowed something very dry and sticky. All things considered, that was entirely possible. He coughed some more, spat out a few crystal fragments, took a deep breath, and finally managed to find his voice. "The scanners couldn't see past the crystal growth. Should've warned you about that. Never got the chance. Sorry. I wasn't quite dead yet, just in a coma. Just like the last time. Hm... This must be a personal record, doing it twice in so short a time."

"Oh! Of course!" Martha exclaimed.

"Anyway..." The Doctor returned his attention to his hand. He brought it to his mouth and licked at the remaining Plague fragments. "Ew. Disgusting. But very interesting, too!"

"Yeah? What is it, then?" Martha asked, sounding a little anxious. "Will you be all right?"

"Oh, yes! This is a good thing, actually." He wriggled his fingers in front of her face. "This is Phase II. Or would've been. Remember Phase II? The flesh-eating phase? Seems I was immune to the Plague after all, partially. It was trying to eat me, but it never got any further than this. I was too hard to digest!"

"So, it's all gone, now? Are you still contagious?"

"Shouldn't be. Let's see." He gave getting up another shot, this time with more success. Might have had something to do with the fact that Martha offered him her hand. Together, they made their way to the computer screen, and the Doctor checked all the readings carefully.

"No sign of living Plague organisms. Good. Still, I'd keep that suit on if I were you. If there's a single speck of the dormant form hiding somewhere, it could spread. Actually, I could use one of those suits. I could really use a shower, too," he noted, scratching at his terribly itchy sides. "But I guess that'll have to wait. Off we go!"

There was a stack of protective suits in the next room. Once he had dressed in one, they did their best to make sure that the outer surfaces of their suits were absolutely Plague-free, and dashed out. They ran into the first locals, a small team of guards, right outside the decontamination room. Without stopping, the Doctor grabbed the sonic and hit the Khiandrians with a nasty, loud ultrasound squeal. As they groaned and covered their ears, he and Martha were on the run again.

Unfortunately, running turned out to be more of a strain than usual. No surprise there, really. The Plague had taken its toll. Once they were out of the building, in the cave chamber where the NTPCRC complex lay, he slowed down.

"Everything all right?" Martha asked worriedly, grabbing his arm.

"Fine, fine. Change of tactics," he panted.

He pointed the sonic at her face plate, turning the clear plastic a little hazy - not too much, but enough to make it less obvious that she wasn't a Khiandrian. He did the same to his own mask. "There. Now, we'll walk. Which way?"

"Let's head back the way I came," Martha said. "Follow me."

They hadn't got far when they met a pair of researchers hurrying towards the building they'd just exited. "No point going in there," the Doctor told them, doing his best to sound like a local. "The alien who had the Plague is dead, and the girl fled. I think they went that way," he motioned in the direction exactly opposite to where they were headed.

The researchers thanked him and sprinted away. For once, the Doctor and Martha were in luck - they managed to escape the research facility with no more trouble than that. The few people who saw them from afar took them for researchers, since the suits covered not only their looks, but also any smells or sounds that might've given them away.

Martha led the way several levels down, into a green tunnel. "We hid over there," she gestured towards one part of the tunnel. "But I'd rather not return to the exact same place."

"Would make us easier to find, yes," he agreed, and headed in the opposite direction. They went down one more level. There, he picked a suitably discreet-looking door, and let them in with the sonic.

As soon as they were safely inside, he collapsed on the first seat he could find, trying to catch his breath, and more importantly, struggling to scratch an extremely itchy and very hard to reach spot on his back. The remaining bits of Plague growth between his clothes and skin were not helping at all. Neither was the smart fabric suit covering it all, as smart as it was.

Martha chuckled, and he could just see her smirking at him through her hazy face plate.

"This isn't funny at all," he told her, pushing at his right elbow with his left hand in an attempt to reach further down his back.

"You should see yourself!" She was laughing in earnest, now.

He let his arms fall, crossing them, but he couldn't help grinning a little - and soon, he was laughing too, not just because of the situation, but because he was so glad to be alive, so very glad to be here with her.

"I'll need to call Khif or Meg to let them know we're all right," Martha said, once they'd both sobered somewhat. "In the meantime, you could take that shower."

"Shower! Yes! Brilliant!" he exclaimed, and hopped back on his feet.

The apartment they were in wasn't terribly big, so he could find the bathroom easily. Cold water felt almost as wonderful as air had earlier. After a very careful sonic sweep of his clothes, both to clean them and to make absolutely sure that there were no dormant Plague bits left, he decided that he wouldn't need the protective suit anymore. He joined Martha at the local terminal, where she was talking to a very serious-looking hologram of Khif.

"I'm glad to hear you're both well," the guard was saying. "Still, we're far from safe. Contrast is already one step ahead of us. They've convinced the media and the guards that we're not just extremists, we're dangerous insurgents. I'm a fugitive now as well, and I've got to admit I'm all out of ideas. I doubt anyone will believe anything we say. What can we do?"

"That's a good question," the Doctor noted.

Martha turned around to look at him. "Hey! You're looking better."

He held out his hand in front of his face. It looked almost normal. The skin was healing nicely, just like it should. Maybe a little slower than usual, but he'd live with that. "More like a Time Lord, less like a red chilli," he said, and sat down next to Martha. There was just enough room for the two of them on the narrow bench. "So, what do we have on schedule?"

"A meeting with the guards, or Contrast, or both, depending on who finds us first," Martha said, not sounding terribly happy. "And the trial is set to continue tomorrow at the first tenth."

"We'll be going, of course," the Doctor declared. "There's nothing like a good courtroom drama! And that bit about meeting the guards, well, we could consider that, too."

"Why would you want to do that? The beginning of the next cycle isn't many tenths away. With a little luck and some skill, I'd think you could stay hidden until that," Khif said. "Besides, that isn't what I was talking about. The Plague, Contrast, what can we do about all that?"

"That's what I'm talking about, too," the Doctor told her, a plan already starting to take shape in his mind.

He had thought he'd be unable to do anything about the general situation on the planet, but maybe he'd been wrong. He'd fixed the Plague, and because it was linked to everything else, he now had the chance to fix everything else, too, if he played things right. Of course, if he didn't, the news about Contrast and what they had been up to could cause even more violence and unrest than the planet had seen so far. There was a lot at stake. Well, he always enjoyed a good challenge. This was going to be interesting.

"Now, do we have any concrete proof of all this?" he began. "I can easily prove that the Plague is of Khiandrian origin and artificial..."

"And K'iem has already let the authorities know about that, and the NTPCRC's dodgy dealings," Martha put in. "Though I don't know if they'll believe him."

"He has? Good for him. Hm. Have we got anything else?" the Doctor asked.

"I have data linking some people in the guard to all this," Khif answered him.

"Oh, very good! Can you send it to us somehow? And could we save it in a concrete, portable form? A floppy, a memory stick, a crystal disk, whatever you've got here? Or put it somewhere safe in the Network that we can access at will?"

Khif raised her eyebrows at his enthusiasm, but nodded. "Meg already has a hard copy of it all."

"We'll get it from her, then."

"You won't be able to call her, but I can arrange a meeting. Let's see... There should be a park not far from where you are. Out of the door, to the left, go on until you find a stream, and then follow that. I'll contact Meg and tell her to be there in half a tenth."

"Good. We'll be there, too," the Doctor said.

"So, you'll try to go public with this anyway?" Khif asked.

"Oh, yes. Very," the Doctor announced, flashing her his widest grin.

"I hope you know what you're doing. Anything else you need from me? We shouldn't talk too long, or they may be able to locate us."

"I think that's about it. Thank you for all your help. Be sure to watch the trial tomorrow!"

"No need to thank me! Thank you, Doctor, and you, Martha Jones. You've done this planet a great favour."

"Not yet, we haven't. But we're going to," the Doctor declared.

Khif cast him a puzzled look, and cut the connection.


	17. The Palace

Before leaving the apartment, Martha and the Doctor dressed in the protective suits again. They would at least offer them a disguise of sorts, and possibly, as the Doctor cryptically added, a tram ticket as well.

They found the park without any major trouble - they only needed to hide from a search party once. Meg was waiting for them under what looked like a tree, but turned out to be a stalagmite with grass growing on top of it. She handed them a small metal disk containing the data. She also suggested she should come with them, to act as their guide, but the Doctor wouldn't let her. "It's too risky. If something goes wrong, the consequences might be nasty. You're better off hiding until we've managed to sort this out."

Martha glanced at him, frowning. "Don't you dare even think about leaving me behind," she told him adamantly. "I'm coming with you."

He grinned. "Of course you are! I said 'we', didn't I? So, bye, Meg, and thanks. Let's go."

"Where exactly are we going?" Martha asked him as they walked out of the park, retracing their earlier steps. She was getting more than a little frustrated with people constantly dragging her along to mysterious places without any proper explanations.

"We're going to meet the Chairperson," the Doctor said cheerfully.

"Huh? How are we going to do that? We're dangerous rebels, remember?"

"With their help," he said, waving at the group of guards approaching them, clearly without the slightest intention of even trying to hide.

The guards surrounded them quickly. They were a meaner-looking bunch than any Martha had seen so far, and she was sure that all the big weapons they were carrying were not just stun guns. Still, the Doctor didn't seem the least bit worried. "Remember, I've got the Plague," he whispered to Martha, and suddenly, lurched sideways to lean on her.

"Hello," he said to the guards. "Took you long enough to find us."

The guards stared at him suspiciously. "No tricks," one of them said. "You'll come with us to the Holding Facility. We're authorised to use deadly force if you resist."

"Oh, but you don't want to shoot me, you really don't," the Doctor said, now sounding weak and tired. "You're going to take me to the Chairperson, straight away."

"Are you mad? We'll do no such thing!"

"Not mad, just very sick. You see, if you don't do as I say, or if you do a single move towards harming me or my friend Martha here, I'll open this suit. Shoot at me, and the effect will be exactly the same," he said, not threateningly, but wearily, like a teacher repeating something for the third time to a really slow pupil. "Any violence, and you could be facing the worst pandemic ever seen in this corner of the galaxy."

The guards were looking more hesitant now. "But - but they said you no longer have the Plague!" one of them said.

The Doctor stood up straight, slowly, as if it hurt. He was doing so good an impression of the sickness that Martha almost started worrying for him again. "Oh, that would be great, wouldn't it?" he said. "No such luck. I thought I had a cure, but it didn't work. You know the Plague. You simply don't get better from it."

"You could be bluffing," another guard tried suspiciously.

"Well, I could," the Doctor said, and took a few unsteady steps towards the guards. "But do you want to risk it? Risk becoming the person who has doomed the entire city, maybe even the entire planet? Take me to the Chairperson. After I've seen her, I'll be all yours. Of course, by that time, I'll most likely be all crystal, too, but I guess you won't really mind that."

"He's dying, and he's desperate," Martha backed him up. "You'd better do as he says. The Doctor's not one to make empty threats. He means every word of it."

The other guards were casting worried glances at the one who had spoken last - she seemed to be the one in charge. She stared at the Doctor in turn, her face grim. "Very well. We will escort you to the Palace. We'll see what happens there," she said, somehow managing to sound as if she was still in control of the situation.

So, they had their tram ticket, just like the Doctor had said. They walked to the First Level, where the guards stopped the first passing vehicle, emptied it of passengers, and ordered Martha and the Doctor inside. They seemed reluctant to come near the two of them, let alone touch them. Now that Martha had a good idea of what the Plague was like, she couldn't blame them. Faking the Plague was a good ploy, like the Doctor's plans usually were. The disease was so scary that even the possibility of it was a very powerful threat.

The part of the city where the guards took them was all new to Martha. After a quarter of an hour of cruising through the familiar, not too wide tunnels, they emerged in a passage almost twice as big as the previous ones. The doors and edifices in the walls were huge as well, every bit as impressive as the entry to the Halls of Justice had been. The tram stopped before the most glamorous entrance of all. It was woven of crystals or diamonds and thin strands of silvery metal, forming a complex lattice, like a very alien variation of a wrought iron gate. It didn't look very sturdy, but no doubt it was reinforced with force fields, or other technological means. Guards in lavishly embroidered silver-and-green ceremonial uniforms stood on both sides of the gate.

As Martha and the Doctor stepped out of the tram, more guards appeared from everywhere around them, these in more functional attire, and armed to the teeth. Some of them even wore protective suits. Martha could also see a crowd starting to gather behind the guards, craning their necks to catch a glimpse of what was going on.

One of the guards in protective clothing stepped closer to address the Doctor and Martha, her face grim behind the mask. "Her Honour, the Chairperson has accepted your request of an audience," she announced, her tone making it obvious that she disapproved of this decision. "You will follow me. Any threatening actions, any failure to do as you're told, and neither you nor any of your friends will ever see your homeworlds again. Is this clear?"

"Crystal!" the Doctor quipped.

Martha had thought she'd already seen all the wonders that the planet had to offer, but once they stepped through the gate, she was proven wrong. It opened into a long bridge crossing a cave chamber, which wasn't very wide, but it was so high that Martha could see neither the ceiling nor the floor. On both sides of the bridge, huge waterfalls cascaded from the invisible heights to disappear into the shadowed depths below. They were perfectly silent, and there was no spray at all hitting those standing on the bridge. Force fields again, Martha reckoned.

At the far end of the bridge lay the most amazing building Martha had seen on the planet. It was all crystal and silver and smooth black stone, and the countless sharp spires, towers and other spiky protrusions gave it a Gothic air. The pale green light shining on it was partially filtered through the waterfalls, and flickered and danced on all the reflecting surfaces.

Martha could've stood there and stared at the Palace for hours, but they were given no time for enjoying the sights. The guards marched them across the bridge at a brisk pace. The Doctor kept shuffling his feet and leaning on her. When she caught a glimpse of his face, his expression looked genuinely tired, and she wondered how much of what he showed was actually real. Martha was feeling a little sleepy herself, in spite of the tense situation. It must be getting quite late already, and she couldn't even remember when she'd last had a good night's rest.

The interior of the Palace was as incredible as its exterior. The countless dimly lit staircases and narrow winding corridors formed a labyrinth even more confusing than the tunnels of Maze City. Martha very much hoped they wouldn't need to try and escape this place, since she seriously doubted they'd be able to find their way out.

At the end of the long walk, they were taken to a room that was far smaller and less ornate than Martha would've expected, more like a living room than a throne room, with a low table and four low armchairs around it. In one of the chairs sat a petite, middle-aged woman with a head of sandy dreadlocks. For a moment, Martha wondered whether this really could be the Chairperson - she had been expecting someone who looked like Neir and Gaer - but the guards greeted the woman with utmost reverence, with salutes and solemn greetings.

"Thank you," she told them. "You may go now."

"But - Most Honoured One, begging your pardon, surely we can't!" the leader of the guards exclaimed. "We can't possibly leave you in the company of these aliens all alone, they -"

The Chairperson stood up. "Thank you, Commander. You may go," she repeated. Her voice was kind, but had a solid, immovable strength to it, like the rock of the planet itself. "And no one is to enter this room again until I say so."

The guards saluted her again, and left, closing the door behind them. The Chairperson returned to her seat, and only then, she actually looked Martha and the Doctor in the eye. "Welcome. Please, sit down," she said, spreading her arms to gesture at the chairs around her. "I've been hearing all sorts of things about you, and we have much to discuss. I'd offer you refreshments, but..."

The Doctor had already landed in the nearest armchair. "Oh, I'd love a cup of tea right now, and there's no but." Before the Chairperson had time to answer, the Doctor had thrown back the hood of his protective suit. "You see, I don't have the Plague anymore. I cured it," he announced brightly. "Although I must admit I'm still a little shaken by the experience. So, tea would be very nice."

The Chairperson nodded at the table in front of them, which was laden with several pots and cups. "Help yourself, Doctor," she said, still appearing perfectly calm, even smiling a little. "To tell you the truth, I suspected as much. Otherwise, I wouldn't have let you come here." She looked from the Doctor to Martha, her pale green gaze keen and piercing.

Suddenly feeling very self-conscious, Martha realised she was still wearing the biohazard suit, and undressed quickly. Unable to think of where to put it, she balled it up between her hands, and sat down next to the Doctor.

"Based on everything I've heard about your actions, I got the impression that you don't want to harm anyone," the Chairperson went on. "I didn't think you'd actually choose to put the entire planet at risk. I'm also quite suspicious of those latest news about you being insurgents."

"Well done, Most Honoured One," the Doctor said approvingly, pouring himself some tea.

Martha thought the world leaders she knew would've considered the Doctor's casual, even patronising tone impolite, but the Chairperson took it in good humour. "Please, this is an entirely informal meeting. Call me T'aikh," she said. "Martha, would you like anything to drink?"

"Um... I'd like some tea, too, please, ma'am," Martha stammered. The Doctor offered her a cuppa, and she had to stuff the smart fabric suit behind her back to accept it. She stared at the cup, perplexed. She found it nearly impossible to wrap her mind around the idea that they'd suddenly gone from being fugitives to having tea with the president of the planet. Had the Doctor known in advance what the Chairperson was like? Had she been less open-minded, this meeting might have been entirely different.

"So, I believe you have a story to tell?" T'aikh said.

"Not a story. The truth," the Doctor replied. "And I've also got a few ideas on what to do about it."


	18. The Great Chamber of Justice

After a few cups of Khiandrian tea and a moment of rest in a huge, soft bed in a luxurious room provided by the Chairperson, the Doctor finally felt entirely back to normal. The Plague was nothing but an unpleasant memory - and a significant political problem waiting to be solved.

He and Martha went to the trial as a part of the Chairperson's entourage. She had assured them that she would only choose guards and attendants she could trust completely, but even amongst them, quite a few were murmuring to each other and glaring at the two aliens. Considering the news coverage they'd had, the Doctor was hardly surprised. He had no idea what the media were currently saying about Martha and him, but he could guess it wasn't anything too flattering.

The looks they got once they entered the Great Chamber of Justice were absolutely flabbergasted. All the other parties were already there. The Fifteen struggled to maintain their composure as they stared at the Chairperson and her unexpected companions, while behind them, the caving team grinned widely at their two friends. The guards surrounding the humans looked like they didn't know what to do. On the defendants' platform in the middle of the room, Jess was waving cheerfully at the Doctor and Martha. Next to her stalactite and stalagmite prison, Neir the spokesperson looked petrified, standing stock-still, all colour drained from her already pallid face.

Ignoring the gaping crowd, the Chairperson led her party to the tier just behind the Fifteen's, across from where the human prisoners sat. The Doctor and Martha took places a few rows higher up, and a little to the left of her, so that they could see her face. Of course, a few of the Chairperson's guards followed them, but they were there to keep the two of them safe, not to protect the others from them.

The Doctor leaned back and put his feet up on the bench in front of him. "This should be a speech to remember," he told Martha.

"I've got my fingers crossed," she replied, sounding so nervous that it was as if she were the one about to address the entire population of the planet.

Once everyone had found a seat, the Chairperson stood up and spread her arms, the wide sleeves of her silver-and-green ceremonial robe flared out like wings. "Honoured Ones, friends from afar, and my fellow Khiandrians, all of you, be you Dark, Dusk or Bright," she began, letting her gaze wander, as if taking in all of her audience, not only the ones in the room, but those watching the news feed as well.

"Until this day, I have not taken part in this trial, as I trusted the Fifteen to conduct it as fairly as only they can. However, as you all know, it is my right as Chairperson to intervene if absolutely necessary, and now, things have come to my attention that leave me no choice but to do so. These matters concern not only the people touched by this trial, but every single person on the planet. Nevertheless, I would first address you, Jess, daughter of Jem, who chose to stand alone, answering for all that you and your friends have done."

"Yes, Most Honoured One," Jess said, making a long, reverential salute, bowing her head and covering her eyes with both hands.

"Jess of Chute Town - or should I say Earth," the Chairperson went on, the look on her face nothing but kind, her voice benevolent. "Would you please tell us what you truly wish to achieve in this trial?"

For the first time during the proceedings, Jess actually looked taken aback. "Your Honour, I -"

"Don't worry, it's quite all right," the Chairperson said.

Jess still looked hesitant, and the Doctor did his best to catch her attention, nodding eagerly to assure her that it really was okay. When she did notice him, she frowned, and looked at Martha, who nodded too.

Finally, Jess stood up straight, head held high. "Very well, Most Honoured One. To put it simply: I took the blame hoping that the Fifteen would condemn me to exile."

A murmur went through the crowd, but the Chairperson waved her hands to shush it. "And why is that?"

"Because Brian is my mate, I love him, and I would rather never see my home again than to be separated from him, let alone allow him to come to any harm," Jess declared, her eyes on her beloved.

The hubbub that rose after those words was even louder, and the Chairperson allowed it to go on for some time before gesturing for silence again. "Thank you, Jess, daughter of Jem, of Earth and Chute Town. We shall return to your case later. I brought it up because it is a fine example that there can be love and understanding between those who are alien to one another, and co-operation between contrasting parties," she said, giving Neir a shrewd look. "On a planet torn in three, it is an important reminder that it is possible to put aside our differences, no matter how great they are. We can all work together for a common purpose, but as with all things, that purpose may not always be beneficial to everyone. Today, in this very chamber, we have two more examples of such collaboration, which I will now point out."

At this point, Neir was looking like she wanted to run away, but a pair of the Chairperson's guards had moved in to stand by her sides, and several more were guarding the doors. In the ranks of the guards surrounding the caving team, a few were looking around or at Neir with uncertainty and anxiety on their faces. One had even put her hand to the gun holster at her hip, but some of the others had noticed that, and were keeping a suspicious eye on her.

"Darks and Brights," the Chairperson went on, paying no attention to what was going on in the room. "The two extremes, with views so different that one would think they could never find a common ground, their extremist groups so fiercely at odds that we're approaching civil war. Who would have guessed that they would combine forces some day? Yet some among their ranks have done so. For many months, probably even years, a group whose members come from both parties has been working to bring down my government and to send us back to the Hive Age, with a Queen on the Throne again. This secret coalition goes by the very suitable name of Contrast.

"Six months ago, they released a deadly Plague among the petromites of Nest Town, and blamed it on aliens. It must be said that they never wished to harm the people, only the little ones. Still, even when the disease mutated and attacked us, they showed little regret. They kept a tight hold on the research facility, hindering the effort to cure the Plague, as it still served their purpose, that of creating chaos, discord, paranoia and hatred. How many of you would have remained moderate in your opinions if not for this allegedly alien Plague?"

She fell silent, letting her words sink in. The chamber was dead silent now, and more than that, it felt as if the entire planet was holding its breath around them.

"Many of you may doubt my words, but there is proof of all these things, and it will be made public. To balance this disturbing piece of news, I will tell you another true story, one of an entirely opposite nature. As I have learned the truth behind the Plague, I have also discovered that there is a cure. That all these news ever reached me is all thanks to the collaboration of several very different people, all of whom took great personal risks to bring out the truth. Amongst these people are Khif, daughter of Khal, of the City of Lights, a Dark, Meg, daughter of P'oan, of Khar's Pit, a Dusk, K'iem, son of Deir, of Maze City South, a Bright, as well as these two aliens, Martha Jones and the Doctor." The Chairperson held out her hand to point them out.

The Doctor and Martha glanced at each other, grinned, and looked around, waving, knowing that for a few seconds, the entire planet was staring at them.

"All these people have been falsely accused of several crimes. The truth is, they have committed no major offences, and the minor ones they admittedly did commit, including resisting arrest and trespassing, were unavoidable due to the difficult circumstances they were faced with at the time. With the right that is mine as the Chairperson of the Planet-State of Khiandria, I grant full pardon to them all, wherever they are. The same goes for the humans Brian, Joseph and Grant, who, contrary to the claims orchestrated by Contrast, have never had anything to do with any violent extremist organisations."

Joseph and Grant were now looking extremely relieved, but Brian clearly didn't share their feelings. The Doctor could see him gripping the edge of the seat in front of him tightly, his mouth a thin line, his eyes fixed on Jess.

"Returning to Jess, daughter of Jem, of Chute Town and Earth, who stands within the Jaws of Justice today: there is no denying that she has broken the Quarantine and Travel Laws," the Chairperson said. "However, had she not done so, consequently meeting these aliens and bringing them here, we might never have learned the truth about the Plague and the people behind it. She also chose to return to Khiandria even though she knew full well that she would be facing charges. She has made mistakes, but her open-mindedness, courage and sense of responsibility are exemplary. Because of this, I pardon her as well."

On the central platform, Jess was leaning on the stone bars of her prison, gaping at the Chairperson as if she could not believe what she had just heard.

"As for those who have worked for Contrast, they will be brought to justice," the Chairperson declared. It was a simple statement of something that was inevitable, and as such, even more intimidating than an open threat would've been. "To those agents of Contrast who are listening to me now: if you surrender yourselves out of your own free will, your punishment will be much milder. I know you're not evil or bad people. You were able to overcome your prejudices and to work together with your worst enemies to do what you thought best for the planet. Look deep into your spirit, and think hard. I trust you to do the right thing. The guards will treat you fairly."

Neir's expression was of pure hatred, but the Chairperson ignored it completely. She hadn't as much as glanced as the spokesperson as she'd said those words, and she still didn't do so. Instead, she gazed beyond the tiers of the chamber, at her invisible audience everywhere on the planet.

"To everyone else, I will say this. I know that you are outraged by what these people have done. So am I. Nevertheless, I ask of you not to go on witch-hunts. Rest assured, we will find each and every member of Contrast. I will not see any more violence arise from this. Do not serve Contrast's cause by rioting and fighting each other. Even if you know someone who has worked for them, do not persecute them. Give them room to think. Let them decide for themselves. Trust each other. These are difficult and trying times for us all, but I know we can follow the example set by the people in this room. We may have different ideologies, but in the end, we all want similar things - peace, prosperity and happiness. We can never achieve these if we don't work together."

The Chairperson sat down, nonchalant, a small smile on her lips.

The perfect silence lasted for almost a minute. Then, all of the Fifteen stood up, and began whistling and whooping. It seemed a little rowdy for such a solemn lot, but apparently, clapping wasn't a Khiandrian custom. Besides, it really had been quite a speech. Of course, the Doctor had given the Chairperson so many pointers that one could say he'd practically written it. Still, it had been even better than he had expected, and he was sure he could never have pulled it off like that.

As the guards around them started cheering as well, the Doctor and Martha stood up and joined in, shouting and applauding - even managing to pass on that alien habit to some of the locals - until their voices grew hoarse and their hands sore.


	19. Epilogue: First Nest

Martha hesitated at the TARDIS doorstep. Even though Nest Town had been declared completely clean and safe, and even though the Crystal Plague now had a cure, she still couldn't help feeling apprehensive about going to the site where the epidemic had begun.

The Doctor stepped beside her. "Come on, they're waiting for us," he said.

Side by side, they pushed open the doors, and left the safety of the TARDIS. Jess, Brian, Joseph and Grant followed them in silence.

Martha had seen several cave chambers larger than the one they'd materialised in, but the khirindal which filled most of it was without doubt the biggest she'd ever seen, a crystal castle almost as big as the Chairperson's Palace. It was also dead - perfectly empty and abandoned.

The room around the khirindal was far from empty. Lining the walls was a large crowd. The Chairperson and her bodyguards stood together with several members of the Fifteen. Not far from them were Jess's sister, her mate and their son, and right next to them stood Jess's parents, her uncle T'ig, and a few other relatives whose names Martha had already forgot. Khif, Meg and K'iem were there, too, as well as countless Khiandrians Martha had never met. They were all smiling, but they stayed still and quiet, knowing full well how delicate the event they were witnessing was.

The Doctor and Martha propped the TARDIS doors open, and Jess stepped inside again, calling the petromites in a strange, soft chant full of clicks and chirps. The alien insects had remained in their hibernation through the short trip, perfectly unmoving and far less glowy than before. As Jess coaxed them out of the dormant state, Martha could see through the doorway how they began to stir, the pale glow growing brighter, antennae waggling and tiny feet carrying them to and fro.

When Jess stepped out again, she was holding the petromite queen in her hands. Slowly, cautiously, she made her way to the khirindal, and a steady procession of petromites followed in her wake. They disappeared between the tall crystal pillars.

Everyone waited with baited breath, watching the continuous line of petromites creeping out of the TARDIS and into the khirindal. As they waited, Martha thought back to the days that had passed since the Chairperson's speech at the Great Chamber of Justice.

Not surprisingly, there had been riots, but they hadn't been very big nor violent. A few people suspected of working for Contrast had been injured, as had a few guards who'd been struggling to arrest some of the more aggressive conspirators. Still, none of that had been major, and many members of Contrast had given themselves up voluntarily. All in all, things had gone incredibly smoothly.

People really had listened to the Chairperson's words, and taken them to heart. During the trip from Maze City to the City of Lights and the awaiting TARDIS, Martha had seen very few people wearing buttons of any colour. The news had reported a significant rise in Dusk popularity in general, and the current Chairperson's government was more popular than it had been in over a year. It seemed certain that T'aikh would get re-elected. If there were Contrast agents still on the loose, they'd probably have a hard time finding anyone sharing their ideals.

To balance the uncertainty and worry about what was happening on the planet, there had been a number of parties. The Chairperson had arranged a small formal gathering at the Palace, to award the Doctor and the humans honorary citizenship - a rare honour, and something that hadn't happened in years. On the following day, they'd had the more domestic affair celebrating Jess and Brian's engagement. Even Jess's parents had shown up to give their approval. Of course, Jess had apologised to her mother for taking her space ship all those years ago. Her mother had smiled, and said that had she known what it would eventually lead to, she wouldn't have been angry about it at all.

The Doctor had skipped most of the celebrations, dedicating his time to the effort to clear Nest Town of the Plague, which hadn't surprised Martha in the least. She was more surprised he had not insisted that they should leave the planet right away. Martha herself had enjoyed the parties thoroughly after all the trouble they'd been through. She had learned, among other things, that not all Khiandrian food was green, and that they did have plenty of drinks stronger than tea.

Now, all that remained was this one last event. They must've been waiting for at least fifteen minutes when Jess re-emerged without the queen, a wide smile on her lips. "The primary queen has accepted this place as her new home," she said, her voice soft but clear.

A wave of relief passed through the room. It had been far from certain that this would work - petromites preferred to build their own khirindals, and they rarely moved far from their home. To these particular petromites, Khiandria was actually an alien place, since they'd been born on Earth. Luckily, Jess had been able to convince the nest that this would be a good place for them.

Bringing the petromites here had been an important symbolic thing, a new beginning, not just for Nest Town, but for the entire planet. It had also been Jess's first task at her new job. She was going to be an apprentice caretaker of this nest. Since she lacked the official training and qualifications, but had a definite talent for the work, she was going to learn the ropes from an older, more experienced caretaker. Later on, once the nest had grown, she would be able to move on to take care of a nest of her own.

Jess and Brian were going to settle in Nest Town, in Jess's late grandmother's home, among the first people to return there after the Plague. Brian would be spending his first months learning the local language and customs. The Chairperson had already promised him a position at the Foreign Ministry as soon as he had mastered those.

For the rest of the caving team, and for Martha and the Doctor, it was time to return to Earth. They exchanged their fond farewells in the shadow of the khirindal, which was now teeming with the tiny lights of the petromites. Everyone spoke in hushed tones, so as not to disturb the creatures, who were just getting to know their new home. Martha hugged everyone - even the Chairperson, since Jess had told her it was a perfectly normal thing to do on Khiandria.

Looking at Brian and Jess, who were standing amongst Jess's relatives, as radiant as only a young couple deeply in love could be, Martha suddenly found herself blinking back tears. She wasn't sure she had ever believed that things could work out this well - that an interstellar love story could actually reach such a very happy end. It had been a long and difficult journey, but it had definitely been worth the trouble.

Martha glanced at the Doctor. He was leaning on the wall of the TARDIS, his hands in his pockets, looking more thoughtful than glad. She knew he hated goodbyes, and considering how many he'd faced during his long life, she couldn't blame him. In some stories, the happy ends always felt bittersweet. She wondered what he was thinking about, but she was also certain that he wouldn't tell her even if she asked.

After one last look, smile and wave at all those who were staying on Khiandria, Martha turned her back to the crowd, and walked over to the Doctor. They entered the TARDIS together.

"So, we cured a plague, prevented a civil war, and brought together a broken family. Not a bad day's work," Martha noted.

The pensive look lingered on the Doctor's face a little longer. Then, he broke into a wide grin. "Not bad at all!"

"What do you think, will things be all right on Khiandria after this?"

"I know they will. There will be bad times, too, of course, but give them a few hundred years and they'll build a society that's widely known as one of the most egalitarian in this corner of the universe. Oh, and T'aikh will be remembered as a chief architect of it all, a renowned historical figure, like Mahatma Gandhi or Nelson Mandela or, or... John Lennon! Hey, we could go and meet him! What do you think?"

"Yeah, it'd be great! Anyway, right now, I'd be over the moon anywhere with an open sky."

"The Moon! Oh, very good, I almost forgot about that."

A little later, Grant and Joseph joined them in the TARDIS, both looking sad and serious.

"Dear kids..." Grant said, shaking his head. "I'll miss them both."

"So will I," Joseph agreed. "And we'll never be able to really talk about this to anyone, nor to tell anyone what really happened to the two of them."

"To think that you spend all your time like this..." Grant said, looking from the Doctor to Martha, his expression more sympathetic than anything Martha had seen on his face before. "It must be very hard."

"It's not easy," Martha replied truthfully. "But we're not all alone, and neither are you."

The Doctor didn't say a thing to that. He was already working at the controls. "So, now that we've got the taste for peace, love and understanding, where better to go than the Sixties! Besides, we have a Moon landing to catch!"

* * *

**Author's Endnote: **That's it. We've come full circle. This is the end of this story, as well as the series that began from Hollow World. There will be no sequels, since I wrote this as a story that takes place just before Blink - hence the Sixties at the end.

I'm feeling a little sad now. It's been so much fun! Also, Solid Skies is the longest story I've written in years, and the second-longest story I've ever written. I doubt I'll be writing anything this long in quite a while.

Hugs and thanks to everyone who's been reading and commenting! Even though I'm such a bad lazy person that I rarely reply to reviews, I really, really appreciate them!


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